pre-diff = setup similar to FWD
post-diff = setup to maximize the newly-found power oversteer.

 

An upgraded rear diff such as the 12 plate one from Shep is what we use almost exclusively here at EvoD. And is in my personal autocross car. It will basically transform the balance of the car. And allow corner exit to become more over steer oriented.

Aero will help any setup, period. But its best to have a balanced setup. And front splitters, rear undertrays do not lend them self to daily driving.

The other thing to think about is what setup you want to optimize. An awesome DD dose not equal an awesome Auto-X car. And an awesome Auto-X car does not = an awesome HPDE car. You will end up making compromises somewhere. That's not to say there isn't room for improvement in your setup. But something to think about.

What are you running for alignment typically? What does your car weigh?

 

This. I went from running -1 in the rear with a full stiff swaybar to running -1.5 and a full soft swaybar. The rear diff mod is one of the most enjoyable things I've done to the car so far.

 

What shops do the rear diff mods? I'm not sure I want to tackle that one myself. I'd rather drive it somewhere and tell them to do it then drive it home LOL!

 

I mean, the dealership should be able to do it. That's how the factory service manual says to build it...

 

Stop thinking STU..

I have had both a 12 plate build from Shep, and the FSM rebuild, I would do the 12 plate if it were not for the class restrictions. I would venture to say that a shop like Shep, or TRE could do it for LESS than a dealership would charge just to reorder the plates.

 

Absolutely, any good local speed shop, or one of the trans shops can do the work. Agile Auto did my Weir Performance 12-plate no problem.

 

Do you recall how much they charged for the work? I want to do the Weir myself, but I'm unsure it will need to get reshimmed afterwards.

 

Good thinking we actually have an excellent trans and diff shop near buy.... which kit does one purchase? Is the Shep one superior to Weir?

 

I think in my case it was 3 or 3.5 hours of labor, for the OEM re-shuffle.

 

^^^^^ Was it worth it?

 

OS Giken is probably the best differential out on the market right now, followed by Cusco and Kaaz, then the other shop ones. The more plates the better, you can always disable them like how the Evos plates came from the factory. With any LSD though, I'd just send the pumpkin and the diff to TRE so he can reshim, do all his fancy diff tricks, oil sight glass etc etc. See sig.

 

Jon also takes forever to turn around, especially as the season is starting up relatively soon. I'd like to attempt the Weir myself, but I'm fimiliar with reshimming.

 

When you reorder the stock diff do you need to reshim? I am not familiar with what the mod requires in terms of tolerances and such.

 

I hate to break it to you but at some point you are going to do some research outside of asking questions in this thread

I would start with these two threads, and go from there.
https://www.evolutionm.net/forums/ev...y-factory.html
https://www.evolutionm.net/forums/ev...ound-here.html

I also agree w/ Brian that if you have the cash and you are not limited by class legality, you should go more serious than just the OEM reshuffle.