here is my view
I don't want to boost the stock motor even in great condition because yeah the bottom might be able to handle it but the SR motor will handle it, I want to push 300RWHP and have seen up to 539RWHP on the stock bottom.
RB20 is too old and too hard to find parts for and if anything goes wrong with the motor then it's going to be a bitch contacting someone from japan to get parts for it.
The CA is also a very old motor, why do a 1.8 when I can go with the 2.0 that came with the motor originally.
I am going to go with a flat black top SR motor, Lsauto exhaust manifold, T28, 3" back, blitz front mount, ect...
I would go RB25 but the the problem is getting the AC to work and plus I don't like the extra added weight of the motor.
SR it is and will be....