looking for suggestions to reduce decibel level of exhaust on my 800 EFI. cannot find any aftermarket products for the dual (crossover) exhaust at this time. are there some ideas out there on maybe a muffler i could fabricate in my shop that would accomplish this that wouldn't require re-adjusting the EFI?? i'm not worried about hp loss as with the 800 there is already more than i need. how much restriction of the exhaust is acceptable so as not to cause problems or warranty issues??