I'm curious as to what the cup air box does for better performance? Also, if you found any negatives to the side mufflers delete. I have the same exhaust setup dropping 42 lbs with the muffler delete along with dropping 100 lbs in other places, I noticed a big increase in performance, but was still somewhat guarded on the mufflers delete as some members had posted that the system was carefully balanced and a reduction in back pressure might reduce the positives of weight reductions. Any thoughts on that issue would be appreciated?