Ok I have a cold air intake(Carb) that belongs to a 99-01 civic. I am running that right now on my D15b. Is that any better then just running the stock air box? Or or should I do a open air. Like just you the neck of the air box and put the air filter on the end or is that not legal either?

 

Do you live in CA? If so, only an intake that is CARB approved for your specific vehicle is legal. An intake that has a CARB number for a d16y8 won't be legal on a d15b.

Just about every Civic has a CARB legal intake available, but they are usually more expensive.

 

Well besides it being carb legal is having the cold air doing anything different from the air box.