Best Handling?????????

5.0 wont keep up, maximum motorsports or griggs can change that though. My guess is that the ls1 would be the best handling. They came from the factory with a torque arm and panhard bar I believe. Others will give you a more definite answer.
 
What do you mean by "3rd gen", 3rd gen what?? Also, ls-1 what? Camaro/Firebird? Vette? Either way, the fox can't hold a candle in the curvies to any modern GM product. The f-body suspension is just incredible. You can carve corners with the best of them, then put on a set of 17" drag radials and cut a 1.6 60ft with bone stock suspension. I hate to be praising GM on here, but I wish I could say the same about foxes. Or any Mustang for that matter.