Blaster running better with stock pipe?

i noticed that with my stock pipe.. it had mucho low end, and with the fmf off my wifes blaster i lost some low end and picked up a hoot ton of mid range.... i have a stock pipe on hers tell your pipe gets here, and hers 'feels' just as fast as mine with simmaler mods
 
yeah most all stock pipes have more lowend punch than the aftermarket o n a stoc k bike