the excess oil from the filter can be sucked in by the engine and coat the MAF.
I have used K&N filters on all of my cars and only one problem out of them all. That was just recently the 740iL, after awhile the Idle Control Valve went, we're not sure if it was the K&N but it could have contributed to it.
On my Pathfinder I have a NISMO CAI, the stealer called me up telling me that he had to change my air filter b/c it was aftermarket.
I told him it's made by NISMO the motorsport division of Nissan, and leave the rest of my car alone!
If anything, every tune up just spray your TB and MAF with every tune up with TB cleaner.
You should be fine.