intakes are intakes, ebay or brand name. the main differances are:

the bracket and support system. an AEM CAI has 2 brackets, an ebay one just hangs off of throtle body

AEM and Iceman are the only 2 CARB exempt intakes. if you live in CA, you won't pass your inspection otherwise

you can reset your ECU after installation by removing a fuse, i'll give you instructions if you need them

also, the 6th gen intakes are not body specific, coupe or sedan, it's all the same. the V6 and I4 intakes differ though.