new headers, x or h pipe and new mufflers

no way will it hurt performance

when you change exhuast you lose a lil back pressure so it will feel slower for those first few lower rpm... but once you are off the line that doesnt matter

i would run mac long tubes and a Dr gas x that would sound sick with the borla... or a prochamber would too its deep and has an x rasp at times that is very sustained.

but you should really look into a stall converter for your aod. then you wont 2worry about any off the line pull and the car will be way more fun all around.

i would want a 3000 stall or higher if you will eventually have heads cam or a blower

with borla i would do an x-pipe...general rule: staright through mufflers do an x-pipe, chambered mufflers do an h-pipe

Watch out for long tubes and Vert's with AODE's. Make sure the manufacturer says they fit.