• cs
  • en
  • cs
  • en


So before the circus begins of this rebuild. We should ask our self why I should change the six-speed manual gearbox from the STI model, for the five-speed from the WRX model. I will try to answer you simply in a few points.

The performance limit of the WRX gearbox

Unfortunately, the standard five-speed WRX gearbox has a limit of 300 horsepower, and since the engine from the WRX is similar in many ways to the engine from the STI, the potential for increasing power is similar to that of the STI, mainly torque. In most cases, the stock WRX gearbox will fall apart at the intersection when you want to make yourself the biggest dude. The STI transmission is said to be made of granite.

Gearbox System and Differential

The standard gearbox from the WRX is differently geared compared to the gearbox from the STI. The WRX has longer gears and this makes the ride feel slower and more boring.


If we look at the differentials, the stock sti has the same "empty" differential up front as the WRX. This differential cannot be adjusted in any way. Some STI models had a torsen type differential between the front wheels for an extra charge, but this too cannot be adjusted. The STI Spec C had a limited slip differential, basically the best you can get. Of course, here the surge of slats can be set. The STI's rear differential has much more clearance than the WRX's. You can imagine the difference when the car slides in the snow in a controlled skid. With the STI, the car skids much more willingly.


When luck smiles upon you and the racing Gods wish you luck. They might bring you a transmission from a newer model STI 2005 - 2007, you will be blessed with the joy of a DCCD inter-axle differential. Thanks to this central differential, the options for adjusting the traction are moved several levels further, especially when we supplement this gearbox with a programmable traction control unit (Ing. Pavel Skácel).

Stregnth and Durability

All STI stuff is bigger, beefier and we can say a lot sturdier. For example, semi-axles are thicker, have larger joints and wider rods. The half axle is the part that suffers the most in Subaru after the engine. Pay attention to the year of manufacture of the axles, axles are not always identical. So what will i be installing in a six-speed gearbox in a WRX? In order for the conversion to be complete, it is advisable to replace absolutely everything that can be found on the STI chassis. Unfortunately, not all of us have a bottomless wallet, so I will mention here the all necessary parts to convert to a six.

These parts are not important to change:

1. Front axles
2. Front axle beam – it is not necassary to change. Unless we want to put Brembo brakes with 326mm dics on fronts.
3. Rear Brakes Brembo
4. Handbrake cables

These are the parts that are important and you must change:

1. Rear Axles
2. Rear differential
3. Rear axle beams
4. Six-speed gearbox STI, incl. Of all holders
5. Complete steering assembly
6. Drive shaft
7. Starter
8. Large clutch set (clutch, pusher, retainer, clutch bearings)

How much will it cost to convert a five-speed into a six-speed?

If we are talking about used parts, the price for a NON DCCD conversion is usually around 70 – 85,000(Czech Crowns). If the transmission will be DCCD and we want to add a traction control unit to the set from the start, it is necessary to add an additional amount of around 30,000,-(Czech Crowns).

What you should pay attention for?

When you're about to start remodeling, it's good to keep one thing in mind. If you are going to buy used parts, try to always buy the transmission and the rear differential from the same car. If you are going to buy parts one after the other, keep in mind the ratio of the gearbox to the rear differential. That is, if the ratio will be 1:1 or 1.1:1.

We're making Subaru with true love and satisfied Subarulovers are proof of it

Thank you for helping me choose a gift for my husband and our Toyka. Jana

Guys, thanks a lot for the handle and the little brakes. Honza Pánka, Yaris GR 2020

Finally someone who has all the essentials at their yard... Petr, Yaris GR

The wheels fit like an ass on a pot. Arcasting really suit the car! Thanks p. Eliáš, Levorg

Thank you from the bottom of my heart for the help with the boxer diesel stuff. I admire your stock availability and especially your knowledge. Sincerely thanks once again. p.Kadlec, Legacy Boxer Diesel

I'm incredibly happy, it's going crazy. Kuba, Impreza STI 2016

I don't understand how you guys do it... Ordered on Friday 5:40pm. And Saturday morning PPL delivered… You guys are Amazing! Honza Legacy Spec B

Thanks for the speed even in this difficult time. Petr, Liberec

Thanks for the borg and pectel support... Josef, EVO 9

I couldn't get bigger discs anywhere for the last model 2018. I couldn't believe it when the guys sent me a picture of the Performance Friction discs where they had 8 sets…Thanks Petr, STI 2018

I didn't want to belive that we could revive our forester again. Once we heard how much it would be to repair at Subaru, we were in shock. Way over our budget. I'm so glad that i met you guys from SubaruSTI.cz Karel, Forestr Boxer Diesel

Thanks for all! Honza, Beroun

I would like to thank you from the bottom of my heart for solving our problems with a broken engine crank. Ultimately, when we calculated the repair costs, we saved 94,000 crowns at your place compared to Subaru in Prague. Martina Urbánková, Outback

Unbelievable patience and knowledge in the field. I almost took our diesel Impreza to the junkyard. Thanks again. Stanislav, Nová Paka

Our good ol' diesel died. We started dealing with the situation by bringing it to a Czech Suabru dealer. UNSOLVABLE! Thanks god we came across these guys. Thank you Subarusti.cz from Peter at Varů Petr K., Forester Diesel

The attitude of these guys are phenomenal. The car brakes, turns and drives as if the STI was brand new. Well I'm happy, my goal was reaching 400 hp. So im completely satisfied. Thanks. Jáchym Novák, Nova Paka, STI 2013

Exclusive support great speed of delivery. Thank you Rosta! Miloš Malchr, STI 2015

6 coils and 4 lambdas, thanks...   Jonáš, H6

!Thanks for the clutch boys, I'm all ready and armored for the winter!   Ota, Impreza WRX 2009

I don't know anyone in Central Europe who would stock Okada Projects coils. Highly recommend! Petr K., Subaru BRZ

I have been dealing with a CEL coil problem for a long time with my BRZ. I didn't expect to buy an original coil from the guys for half as much as from Subaru. I recommend. Jenda, Subaru BRZ

Thanks guys! Finally my BRZ is braking again. Kamil, Subaru BRZ

Nobody seems to have anything in stock for the BRZ until I came across a shop full of STI parts. The next day I was already braking and bragging on Facebook. Martin, BRZ

My EJ25 had a blown gasket. :( Thanks to the guys at subarusti.cz, i got in touch with the perfect Subaru service. Today i even had it forged. :) Great attitude. Martin Krobs, WRX STI 2011

At 23:30 in the night, i shot them an email for fun for a exhaust for my Subaru Levorg, even though it wasn't in stock on their e-shop. Fast forward 4 days and we're assembling the exhaust in the workshop! Perfect approach and advice. I mean i guess thTomáš, Levorg

Unfortunately i was met by a knocking engine. And at first i didn't know what to do. But thanks to Rosta's patients, he was willing to spend 100+hrs with me on the phone to sort everything out. I admire his work and customer service towards his customeMichal Janotka, STI 2008

Thank you subarusti.cz for the porn! Filip, Forester Turbo

Finally, things are moving a little and the STI is finished, thanks to Mr. Daněk & Fejfar. Great work and many thanks to 4turbo.pl as well Pepa, STI 2006

I would like to thank SubaruSTI.cz for a great job. They have advised me which downpipe would fit on my car and it fits perfectly. And other dealers have informed me that this part still needed to be serviced on the car. Josef, STI 2006

Finally my brakes are all sorted out, thanks to you guys. Thanks SubaruSTI.cz, means alot. Zbyněk, Legacy SpecB

When this comes to you in the mail, it means only one thing... You have left a lot of money. Thanks for the great service and advice. Michal, Impreza WRX 2004

Thanks a lot, great satisfaction. I recommend Subarusti.cz. Jirka, WRX 2006

Thank you very much! - very friendly dealings - perfect attitude - processing speed - limitless knowledge of Subaru - excellent advice. Lukáš, VW Bus

My experience, staisfied to the max. All i can say, I recommend. And great experience they have with subaru. Marko Holyday

I recommend! Willingness, quality, great prices and great people. Lucka M.

I can only recommend, fast delivery, help and willingness to advise FuGas

I can only recommend. I bought brake discs, brake pads and etc. Great communication, price and willingness to advise.Lukáš Mihalik

Quick dealings, sending the package and above all the quality of the products. Jan Sanny, WRX 2003

Excellent communication with the seller even after the purchase of the goods and assurance that everything is OK. Furthermore, a good price and a personal approach are the main reasons why I would recommend the store to others. Jirka, Subaru Impreza WRX

Excellent communication, super price and super personal approach. Jarda, Subaru Impreza WRX STI 2008

Thank you for the fair dealings and fair handling. Kyslík, Subaru Impreza RA

The bumper is in great condition. One hundred percent I will contact you again and I am really excited. Lukáš K, Subaru Impreza WRX STI 2006

Rosta, thanks for the info and you put my mind at ease. You are really cool and deserve a really big kiss from me! :-DMartin, Subaru STI 2011

I can only recommend! Dealing, approach, quality of goods, willingness and experience of a true Subaru owner :-). He will recommend the best choice and in case if your confused, he explain even for those who do not understand.Dominik, Subaru GT

Completely professional approach, communication without a problem. I RECOMMEND.Karloz, Subaru GT

Completely professional approach, communication without a problem. I RECOMMEND. Lukáš, Subaru WRX

I recommend! Great handling and fast dispatch of parcels. Perfect communication and knowledge everything about Suabru . Otík B., Subaru Impreza WRX 2004

You are here

  • Main page>