Thanks all for the input, it really helps.
Well cost isn't my greatest concern, I decided against buying a different car for 5 grand and am planning on doing the pintara up a little bit...was going to sell it to my bro for $500
So far its just been general home service stuff, oil/air filters, brakes, fixing rust spots etc. and I bought a new set of rims($1500).
But yeh $2000 might be a bit over what I want to spend on the exhaust alone. Its probably the only 'known' problem the car has at the moment (touch wood) and I figure if I'm getting a new one that'll cost $200 may as well get one that'll make the car go/sound better for a few hundred more.
So from what I gather, extractors are nice but not worth it, 2.5" is the safest bet, need a high flow cat or one from a v6 magna(or similar), go to an exhaust place that won't rip me off. I know the last one is almost impossible but my dad is good mates with a guy that works at a local exhaust joint so I'll get him to take it in.
People keep saying 'most off the shelf extractors aren't worth it', does that mean there are some that are? and should I just get them anyway, it is my money being 'wasted' after all lol
Thanks again for the replies everyone.