Opened up my airbox yesterday to find a K+N panel filter. Looked in pretty good condition although i don't know when it was last cleaned. I knew the car sounded a little throatier than it should lol. Anyway, what is the general opinion on these for this engine? I've heard stories of the oils ruining the maf etc. There are no other mods, would i see a MPG increase if i changed it back to a standard filter? Lastly, my exhaust is blowing from somewhere around the middle, so looking at my choices for an exhaust. Any recommendations? Again i've heard aftermarket can be bad as they aren't tuned to the engine like OEM.
Any thoughts/advice/links to recommended products and general "spoon feeding" appreciated