New Owner - Suggested starter mods

[TriTard]

Im buying a '03 G35 sedan tomorrow and im wondering what are the most common/best starter mods for the car? I already plan on getting an injen cold air intake kit and maybe some high flow cats. any other suggestions that are on the "cheap" side?

another question. does water get into the injen cai when its raining?

[Fezzik]

Usually water will not go into the injens. Now if you go into a foot of water, then yeah, you may. Maybe a catback exhaust, headers if u want but most people do cats and back.

[TriTard]

i dont think im gonna do headers, at least not yet. i dont have the equipment to swap em out and dont rely want to pay someone to do it. if i wanted to upgrade the car's computer system to squeeze out a little more power, is that relatively easy? in other words, are there chips that i can just replace the old stock one with?

so the injens wont "suck" in water? thats good to know but it still worries me a little bit.