I recently purchased a set of Cooper RS3-A 235/50/18 (all season performance variant) tires for my 2008 GT and I am VERY pleased with these tires. They are a better tire than the original BF Goodrich G-Force T/A's that came with the car in every way imaginable.
First, they have a more all-season tread cut to help wick water away from the tires when you get caught in the rain. I normally won't take my Stang out in the rain but its nice to know that if inclement weather strikes while you're out in the car that you are riding on a set of tires that aren't akin to driving on a frozen lake.
Secondly, they handle AMAZING. No more tracking along grooves or uneven pavement surfaces like the BF's did, where you're fighting the wheel to keep the car aligned in a straight forward direction. That was a really annoying problem with the Goodrich tires. These are performance
tires and they handle like it. They just offer more, especially to the guy that drives his Mustang GT daily (I don't).
Third, they are quite a bit cheaper than the BF tires. I paid $182 per tire at Tire Discounters (I know, I know...NOT the cheapest place to go) with their add-on $24.99 per tire charge included in that price, so it was just under $800 for a set of four tires.
Fourth, they LAST LONGER than the BF's do. A LOT longer. They are rated as a 500 for tread wear as opposed to the BF's which were (I think) a 300 rating. They also have a AA traction rating and an A temperature rating.
I do realize that this tire is NOT marketed as a "Summer Ultra High Performance Tire" like the BF tire is, and that the higher tread rating is due to a harder compound than the original tires, but I can tell you that I am still looking for the trade-off in handling on dry, warm pavement between the two sets and I am not finding it. If you MUST have an "Ultra" Summer tire, Cooper also makes an RS3-S variant that is similar in nature to the BF tire, but even still gets better marks in almost every regard from what I have seen online.
If you're looking for a good tire to put on your Stang, these are it. Do the research: this is a fairly new line of tires and from everything I have seen online (and now in my own experience) they are an incredible tire for the price.
They also hold a shine really well which is important to me as I like to keep my ride looking SAH-weet.
See for yourself: http://www.treadepot.com/review/zrs3a.html
Its a GREAT tire and it looks awesome...and performs well and won't break the bank. Anyone else tried these on their Mustang?