had a shop cut off my cats and weld pipes in their places... cost me $80 (this other shop was gonna charge me $100)

i can feel the difference, for REAL the guy also told me both my cats were clogged to death. oh well

now... my car backfires a lot, is that alright ? when i give it gas sometimes it back fires, but when i let off the gas and im cruising at 40 or something, i can hear it backfiring even without me pressing the gas. if it's normal for cars to backfire, then ill leave it alone, but if it isnt... then i gotta do some fixin' hehe

also... i think the AIR pipes are hitting against the exhaust pipes cuz sometimes i'll hear a noise that sounds like 2 metal pieces hitting eachother. how should i remove all the AIR lines? do i need a lift, or can i just jack up the car? thanks guys