thanks for all the info. i'm currently using a rep carbonio intake with k&n drop in. i'm getting some fluttering noise from turbo between 3.5k to 4k rpm. but from 4.5k to redline, the engine pulls amazingly smooth. don't know wat's the problem but will play around with intake before messing around with other hardware. may try to use stock intake box with k&n drop in only.
any difference between pipercross filter and k&n drop in?