Exhaust pipe size

well it looks like 2.5 would be the way to go....so 2.5 it will be.

As far as for headers, i'm really not sure what to do. Headers like Hedman (let's call them the affordable one), are a major pain to install and, from what i have read, have some clearance problem to ground.
So I tought that I would wait until I can afford a set of TTI, wich is not for now.
Will there be a good performance gain, even with these "affordable" headers?

...the other thing, is that yesterday I discovered (i'm newbie) that to install a big block you need a kit, like Schumaker, to swap, and that mostly it (well plus a couple of other thing a guess, but still...)!!! So will it be 383/400 8):D or a 360 ... i will have to think about that also.