yeah, i got a cai from ebay a couple of months ago and fitted it with a k&n filter , the piping is 2.5' and the performance kinda tends to suffer a bit on the low end, but thats just coming from me, the mid range is where the power shines, and it kinda sorta stays the same, if not improves by a little on top end.. all in all, good deal for $120 including the k&N filter...
but am planing on purchasing a AEM cai in the future
Frank