Hi all. I am picking up a 07 ST4 with the Northstar V8 this week. The dealer is having a few things done at the body shop for me. It is loaded with heads up, nav, heated/cooled seats ect... It is the dark purple color, kinda cool. I have a vision for it and will start mods soon. I have had MANY GM cars and am looking forward to get back into a V8. I am trading an Audi a4 turbo. Need something bigger.

The car has a STS-V style grill that I am not a fan of. I may be selling it....

Any suggestions on engine mods aside from CAI and exhaust?