That sounds like a fun suggestion! However, the newest Mustang I can find on craigslist is an 03 for $4500. I think cars are a bit more pricey around here than most areas. In comparison, the Cobalt SS I may be looking at tonight is 0-60 in 5.7s. That is before the boost increase tune the owner did. It is also rated higher by the EPA. I'd imagine I could get high 30s, low 40s with it. Though the Mustang adds rwd which obviously has its benefits and draw backs.
Here is the Cobalt I may look at tonight if the seller gets back to me...
2008 Chevy cobalt ss turbo