I’d have to say the GT500 is tempting, especially since you can get one with 2k miles on it with SVT for mid 40’s. One thing to consider is the 2011 GT500 is a fair bit better than the 2010. It doesn’t suffer from heat soak as much and with the aluminum engine is 100-150lbs lighter over the front axle. Ford also did a fair amount of tuning to it.
I think if you want something that you can track the Boss 302 might be the better option. Higher redline, lighter and should be more nimble. I do believe that the Boss will outrun an M3 on the track (driver dependent of course).