I just installed one on my friends 07.
He put down 460 @10 lbs. on a very safe tune. (stock block)
issues I had:
1. The strut bar does not fit, not even the gt500. Hits the air filter
2. The eibach front sway bar cannot be used, it hits the crank pulley, have to use the stock swaybar.
Other than those 2, nothing major with the install.
As with any power adderm it all depends on what type of power you are looking for. Do you want instant torque? if so look into a positive displacement supercharger (the ones that sit on top of the manifold). Do you want progressive power? then you would be interested in a centrifugal supercharger, (procharger, paxton, vortech...).
Then there is turbo, but that is a different animal all together.
Best of luck.