....... I am waiting for someone to chime in here...

Stock hp for a ZC -137
Stock hp for a B16A -160 and up

So tell me, what is the aftermarket parts availability for a ZC vs. A B16A ?

Dily driver/ weekend autocross, I would do a Z6 swap with a turbo. If you want to go a cheaper route, I would get the JDM B16A. It is a fun motor..

There is a reason the ZC's are so cheap....