I hate to break it to you Matt, but a IRS, '03 Cobra handles pretty well. Light mods on any of the cars you mentioned will result in a Mustang disappearing into the distance, on any track.
No underestimation here. i understand what it takes to go fast. FWD is off the list. So are 4 cyls. Can you put one on the ragged edge & go fast, yep. But don't forget, you are on the ragged edge.
Don't overlook the fact that I'm not talking about some clown in a Mustang either. Here's one to check out. 8.80 Daily driver.