One other thing.... Make sure you get a good pair of subframe connectors as well. They are a MUST for all mustangs, especially convertibles. If you have gears and are blasting off the line, its not good for your chassis at all. My friend ended up cracking his floor boards from blasting off the line in his convertible, because he had no subframe connectors. And that was just with 3.55s in an AOD!

WOW!!!! Ok, twilight blue gt. how much are subframes, and what are a good brand? I have heard that kenny brown makes good ones... Can I install them myself?

I have kenny brown subs on my car and I love them! What a difference I felt once they were on! Much better handling and it really stiffins up the car a whole lot. I got mine off of Mustangweekly.com for $95. My friend welded them on for me.
You can put them on yourself if you know how to weld good. All it really involves is getting the car on jack stands and welding.