I'm a Mustang owner's since 1983 and I will never forget the fun, I have with them...
Last week, I just buy my 14 brand new Mustang's, it's a super rocket bargain compare to my Z06 Corvette 2003 and my two children's can ride with me also...
I got my 2004 3 months ago and there is a lot that can be done to these cars to really wake them up.
A important word to take in caution. FORD my monitor the forums and whatever you do DO NOT play with your PULLEY or your warranty will be VOIDED. If you don't care about warranty and only want MAX power then knock yourself out and go form it.
We've got a bunch of great guys on the forums and everyone seems to be very helpful. Enjoy and be careful.