Hey Everyone,
I am gonna ask the question that I am sure has been asked many times before, but unfortunately, nothing turned up in my searches. Before I start on my RX7 project,which will be for the purpose of tracking the car, is the S5 TII really that much better in the end than an S4 TII? I see that stock, the S5 TII kicks out a little more hp than the S4, but since the S4 TII engine has a lower compression ratio, wouldn't that mean that it could also support more boost? Also, I know that the S5 has some differences in the porting, I believe in the exhaust if I am correct, but other than that, would I really be that much better off in the end? I did read in a few places that S5 parts are much harder to come by over the S4, so is it really worth it? Any opinions on this would be of much help. Thanks!

Jason

 

S4 also weighs less. (No motors for the seat belts, etc) has the more desirable clutch type Limited Slip versus the S5's viscous type...