my wife and i just bought a 2003 mach1 for her. (you should read that 'for me'!) i have to say, that is one bad @ss car. wow. it's black w/black stripes, real shaker hood.
lol, thanks! i have to admit, i know nothing about newer mustangs, so i don't know yet. she already gave the thumbs down to new exhaust (i am going to have to work on her about that). when i mentioned louder, she crinkled her nose and said 'i don't know' as if louder were a bad thing! since it has all this complicated computer stuff, i am hoping i can swap a chip for more power. not that power is lacking w/ 305 hp.
I wouldn't worry about a chip just yet. The programs in those are pretty good. And having the mass air meter makes it more forgiving to any mods. I hear gears are an execellent upgrade for those cars. Something in the 4.30 range. Give her a couple weeks to get used to the sound of the exhaust. Then she might not notice if you change it to something louder.
Sometimes I feel lucky. Anytime I talk about changing something on any of my vehicles, she just wants to know how much it costs.