Aftermarket Flywheel and counterweight compatibility questions

[Roen]

It's based off the rotors in your engine. If you use S4 rotors, you need a S4 front and rear counterweight, same with S5.

When installing flywheel, you only need to concern yourself with the rear (automatic) counterweight.

If you plan to swap rotors in your engine, for example an NA S4 engine wanting to use higher compression NA S5 rotors for more power, or a turbo S5 engine wanting to use lower compression S4 rotors for more boost, you will need the rotors, plus the corresponding front counterweight and the corresponding stock flywheel or aftermarket flywheel with corresponding rear counterweight.