[spuggy]

964 generally gives slightly more power at high RPM than SC, at the cost of less low and mid range torque.

I'd be surprised if 964 made more than 5% difference to peak HP over SC - and for a car that sees street time, I would just stick with SC unless you have EFI - on the grounds that you'll probably never notice 5% at WOT - but you'll feel low/mid-range pickup every time you accelerate in traffic.

You can experiment with the SC cam timing to move the power band around, see if you like this/can put up with it, without needing to actually change the cams out. Factory used the same profile for a long time, with varying timing specs for different years.