on 2 previous cars i've had k&n filters, no problems at all. also had an apexi.
over 4 years and on 2 different mr2 turbos i had a metal blitz filter for about 6 months, then ran the k&n for 3 1/2 years no problems at all.
the other mr2 turbo ran an apexi with no problems at all.
a k&n also...