MAF questions

[JackieFan]

How restrictive is the standard S12 MAF? Would we gain anything by using one from a different car? Is it even possible? I've got hold of an old Z31 MAF on the off chance but I only want to piss around with it if it's going to be worth it.
We're not looking at changing the intercooler and piping anytime soon but I was wondering if the inlet to the turbo was a bit more free flowing would it make a noticeable difference to spoolup or top end performance? Or is it the case that to make any real difference I'll have to change a bucket of things?

We're running a T25 with standard injectors(although I've now got some S13 ones) standard head and cam with 2.5" straight through system with single Chav cut back box! Innit!