When you say custom is too expensive what kind of custom are you talking about?
I just pulled out my big reciept book that came with one of my cars and there's a reciept for $350 that paid for a 3" pressbent aluminized catback w/ muffler at Budget brake and muffler. Yeah it's aluminized but that reciept was also from the end of 1999, it's 2006 now and there's nothing wrong with the catback, it's still in pretty good shape.
If you can't afford to buck up for a 3" mandrel SS turbo back then just have a 3" pressbent aluminized made up. Any shop can do that. Just get some pictures of a 'normal' aftermarket 3" exhaust, it goes basically straight and has about 2 kinks in it ad hanges under the rear suspension. I think a factory exhaust might go up over the axle but truth be told I've never seen one.
Especially if there's a muffler shop around you that does V8s performance stuff. Just bring in some pics and I can't imagine them having too much of a problem doing it. As far as performance of a 3" pressbent catback vs 3" mandrel I bet it'd be negligible. I've switched from my stock dp/cat/3?pressbent to a mandrel 3" turbo back, no cat and noticed a difference but it's all in the DP and cat. Later on when you have some bucks you can always have a 3" madrel SS downpipe made.
