Hey, i have 2000 v6 mustang 5 speed with cai. I didnt really want to mod my car due to it not being a gt but i recently went to my local ford dealer to have my engine light checked and it turns out i have some exhaust problems "cats and my pipe". they want 2400 to replace it and i know i can get a performance exhaust for much cheaper. I was looking at am.com and was thinking of long tube headers, h converter pipe, high flow cats, and gt flowmaster catback. My main question is will i notice more power and mpg? and will a tune help? I dont wont to do serious mods but i figured im gonna have to fork up the money why not get a better system. a local shop said they will install it for 220. ( im 18 so im on a tight budget and my dad pays for my insurance so a gt is out of the question to him)