ok, im swapping motors between my friends two cars; both s4. one motor is blown but has a good clutch, the other motor is fine but has a crappy clutch; when putting the good clutch on the good motor, do i need to swap flywheels too or is it ok to use the good clutch with the flywheel that had the bad clutch on it?

 

It would be better to keep the complete cluch unit and flywheel together, a lot depends on how bad the bad flywheel is.