Go dry - K&N oil can mess with your MAF. It happened to me, it's happened to others.

I supercharged, then did exhaust work (2.5" pipe from the cats back and a high-flow Flowmaster muffler) and I was equally impressed with both mods. Opening up your exhaust will release some low-end grunt from the engine, and it's a fairly cheap mod, too. I began to chirp both front & back inside wheels turning onto a road from a stop after the exhaust mod, whereas I would only chirp one before, and only sometimes. It's more useful power than what the S/C adds since it's down low in the rev range where the engine spends a lot of time (the S/C only starts to play at 4500 rpm).

Good luck!