I've never had a problem with K&N's. I've run both panel and cone filters of their for years. I've heards of the oil messing up MAF meters, but all of the cars I've used them on have had MAP engine managment. I believe the NSX is a MAP system as well, but I'm not 100% on that. On the dyno, I actually showed 1 more HP with the K&N than I did with an open pipe.