I finally replaced the air filter with a K&N replacement panel filter. Now I get to hear a little whine from the S/C, which is nice. I haven't noticed any power increase and it is too early to tell if mileage has increased.

One odd thing is that now the exhaust seems to pop under deceleration. Stock exhaust with pig snout tips. I don't mind it, just making a note. I think next I will change the mufflers to some Borla with some resonator exhaust tips.