A couple things to look out for with the 2011-12 5.0s are the MT82 trans and cylinder 8. They have heat issues in cylinder 8 and they like to go up quick. I would do a compression test to make sure the motor's fine, before even considering it.
Definitely test drive the car and go through every gear to make sure it goes in smooth and doesn't whine. After the test drive, leave the car running and smell the exhaust, just to make sure it doesn't smell of oil.
The 5.0s aren't as rare as the Nismo Z, but man are they fun to drive. They handle exceptionally well for being what they are.
Or you know, if you want big power and great handling, you could always put a V8 into a well handling car.
