Originally Posted by ejazbmw
i don't understand these things lol do you need a after market intake for these? is there a sound difference?
they channel the air to the intake box. you do not need an aftermarket intake. you see the most gains at high speed (highway), because air is rushing at the car at a high rate of speed and and these help direct the air into the intake. this way you get the best efficiency out of whatever intake you have, whether stock or aftermarket. without these, the air doesn't get "forced" into the intake.
Personally, i think a very nice upgrade.