I have the front solid mesh piece off on my lancer where the cold air filter sits. My question is.....if you keep it off in the rain will it damage anything internaly?

 

I have driven with the front solid mesh piece off in the rain tonnes of times.....the harm to your car is negliable...its about as harmful as rocks denting the ridges in your Filter......the only really way to **** up ur CAI is drive in a flooded area.

Putting the solid mesh back on your bumper would essentially vitiate any gains from the CAI as it is drawing air from the engine bay and not outside......AEM and Injen created the CAI in that way for a reason....so you can take the vent off and essentially have RAM CAI....

 

you shouldn't get any damage. The chances that enough rain drops to hydrolock the engine would penetrate the filer, travel 3' up the tubing, through the MAS, and into the engine are very, very slim. Look for the thread about hydrolock in this forum. The author (I believe is Pisetup?) made sure it would show up in searches for key words hydrolock, intake, CAI, and others.