ok im going to do s5 na rotors in my s4 tii. Just to have a little higher compression. I already have a stand alone so no need to worrie about tunning an all that stuff to compensate for the higher compression. But my main question is do i have to change the front counter weight under thefront cover. Or no do i leave my stock one in that matchs the flywheel.

 

ok i need the flywheel an the front counter.

 

I believe S5 counter weights should be matched with S5 rotors.

 

Bump

So I'm also pretty sure that the front balancer needs to match the rotors.

If you use a rear counter balance from an automatic when you install an aluminum flywheel, the counter weights are the same for both an S4 and S5. Hope this makes sense....

 

You don't want to run the s5na rotors in a s4t2. The bump in compression is going to make high levels of boost very dangerous. If you are running it in a non-turbo configuration then it's fine. But for a turbo config stay with the t2 rotors so you can run more boost.