I have only built a couple , and always used turbo pistons with spacer or stock comp.
Its going to depend on a few things, how much power are you after? what wheelbase do you want to run? which turbo kit do you have?
Generaly if you put in a spacerplate turn up the boost a couple of psi and you will barely notice the change in bottomend and gain a little in top.
Take note of comments about squishband in another thread, for the same compression the correct squish (piston/head clearance) will reduce the chance of detonation.