i'd like to get an AEM CAI but if anything over a 2.25" exhaust would damage mid-range power on my D16Z6, wouldn't it be the same basic principle apply for an intake?

 

no...

that rule of 2.25" or less for a small NA motor such as the one you have, has to do with a rule of BACK-PRESSURE... raising that size for the exhaust air to exit, decreases back pressure.. which is bad in your case. opening up the intake path isnt about the diameter of the piping because the motor is only taking in as much as air as its cylinders can suck in.. the bigger the pipe will smooth out the flow of the air coming in and increase the velocity it travels in as well....the power in your rpm band will be smoother.. but thats about as much as its going to do... intakes on these motors are for sounds and a little better gas milage and to free the flow of air, combined with an exhaust and a header you possibly might gain a few whp... but nothing amazing..

thats it, in a nutshell

 

a few whp is all i'm looking for, so that sounds pretty good, thanks.