e series or r4

will a e series or a r4 slip on flow more on a modded 400. like piston and cam?:square

Will it flow more than a stock muffler...................yes. But won't make a difference like a new piston and cam if I'm understanding you correctly..

MODDED AS IN USING A PISTON AND CAM.
E SERIES VRS. R4 USING A FMF POWERBONG HEADPIPE
SORRY I HAD THAT WORDED WRONG

Yes sir it will help....are ya runnin a powerbong with a stock muffler. I never tried it but try the modded stock muffler changes that are posted out here...It'll save ya money..and should meet your needs...:D

RIGHT NOW I HAVE A E SERIES WITH STOCK HEAD PIPE, K&N, NO AIR BOX LID, 155 MAIN AND 42 PIOLT, SPARKS ADVANCE KEY. I AM INSTALLING A GT THUNDER 12.5 STOCK BORE PISTON AND CAM AND THE PEOPLE THERE SAID THAT MY EXHAUST WILL BE HOLDING ME BACK. I'M TRYING TO FIGURE OUT WEATHER TO KEEP THE E SERIES AND GO WITH A POWER BONG OR SELL THE E SERIES AND GO WITH SOMETHING ELSE. I DRAG RACE AT A TRACK HERE ABOUT 100' SHORT OF AN 1/8TH. THANKS FOR THE QUICK RESPONCES!!:devil