what is a good aftermarket LOW DBS pipe? --- i'm porting/polishing/lapping/boring my 400ex out and was advised to get an aftermarket pipe for it to work properly. i would rather just get a silencer with a quiet core instert? but idk if this will work.. with all that motor work i prolly have to get a header? if thats the case idk if i have the money for a fully system, so would a header with a bigger insert work?