here just read this link to a post I made almost a yr ago about cold air intakes and mods, it covers the pros on cons
http://www.the370z.com/nissan-370z-g...-hp-gains.html
Probably the best mods you can really do that are worth while, is really anything for maintanance and reliabilty and suspension and braking , tires etc. As the car comes stock, it has more than enough power/speed for the street or track days.