I have a 03 350z and i want to start modding it. I'm going to start with a CAI, i was wondering if having a cold air intake that is almost right infront of the grill would have any problems with driving in rain, thanks

 

No, unless its a torrential downpour that allows the motor to get hydrolocked, you'll be okay. BTW, the Z doesn't have a "grill" per se, so I'm wondering where you are worried about mounting that CAI.

 

My CAI goes to the fender well

 

well, i have mine with the AEM one, which is basically the same as the NISMO one :
with these attachments: and
it has worked super great till now, almost a year that i bought it, and you can feel the power almost instantly.

My recommendation, if you buy one, no matter what you buy, at the same time disconnect the negative from the battery, and clean the throttle body and flow meter sensors, you will feel the difference