I am confused I just picked up the cobra 6 into 6.I ran them Saturday without the baffles WOW

I just called cobra and a rep said this could make the bike run lean. My question is, How could that

be. The a/f ratio has not changed, no different air filter and the change was after the CAT.

Any input would be grateful.

I even unhooked the battery during install to allow the bike computer to adjust