Picking up a 2009 GT500 convertible, triple black, 13K miles, stock, as a father/son project. We want to start putting together a list of the most common and popular mods. Start with the small things that people change to make the car better and maybe work our way up to a 2103 TVS swap. Maybe lower the car and improve handling? CAI? Exhaust system? Should we improve shifter? Let us know what improvements you made that were well worth it and what changes you made that you wish you hadn't - hoping to learn from experience!