just got '06 GT vert, want supercharger

Not trying to be mean,but you really should search.

Yes you will need to tune it,best on a dyno rather than a supplied "canned" tune.

Yes you and your buddy should be able to install it,some are easier than others.

Yes your factory warranty will be voided.

The intercooled procharger kit seems to show the most gains per psi,and you don't have to tap into the oil pan for the oil supply,which makes it easier to install,and to uninstall if you try to get warranty work done without the dealer knowing.
Vortecs are very reliable,but you have to tap the oil pan. They also offer two kits,a non intercooled kit,and HO kit with a intercooler and more boost. Both the above SC's will be high rpm centrefugal blowers(mount to engine by brackets,and supplies boost to the motor via piping).
You can also get a KB,its a roots type twin screw that mounts where the intake is, which has major low end power/boost,and makes for better/funner street driving. The saleen blower is a good safe(low boost pressure) roots type which looks very nice and clean under the hood like it was meant to be there.It makes good power too considering the low pressures.

My wife just got the same car and was thinking the same thing but I told her how much it would cost and she would have to wait but she could drive my truck if she wanted to go faster

The Kenne Bell is a very nice piece. Even at lower boost levels 6-8psi it makes great power and torque. http://www.kennebell.net