do you have to use rotors, e-shaft, and both counterweights from the same engine for it to balance out right?

 

bump mang

 

Rotors and counterweights(or flywheel) are matched.All 4 must be a matched set to maintain balance.Dont think the E shaft matters,since its balanced by itself.
For 2nd gens its S4 and S5.
1st gens have 2 or 3 types depending on year and engine type.

 

so all s5 rotors and counterweights are the same? or they're all different

 

Yes, they are all same.

 

Except compression ratios,between the N/A and TII rotors.....

 

Yep, just to back up previous respones, all 13B e-shafts are compatable. As long as you are using all S4 or all S5 rotating parts (rotors, front counterweight ,and flyweel) it will be balanced.

 

That implies an RX-8 e-shaft will be a direct swap in. Is that true? If so, any advantages to doing it?

 

different stationary gear set up