l bought a 2006 silver Inifiniti G35.It has 19'' wheels, navigation, black leather, etc, so I am not looking to make many appearance/entertainment mods, other than a sub.I am looking for any ideas for performance modifications that can be made?
FYI, l just bought it and have no intention of selling it anytime in the next 10 years.So, l really do not care about the resale value, this is just going to be a fun toy for me to play with.

Buy an intake system, full exhaust, chip the car, Headers, and if you're going to want to get some serious power, a turbo system, or supercharger. If you'd like more details, with either what brans to buy, or if you do not want trouble with passing emissions, than do a cat-back exhaust system.

when people like you start trying to making a car.of this caliper do what it wasnt designed to do only makes the car worh less no one wants a shitted up car

See link for list of performance mods you can do for a G35 ( l assumed that you have the coupe but if you have the sedan, it should be about the same. Stillen just does a great job with INFINIT l and Nissan mods. good luck !!

Add junk onto it and you will have a hell of a time selling it.