exhaust core size????

[roostX400]

hey guys im running a curtis sparks full exhaust system on my bike, the core for the muffler part (can) is 2 inches. now the pipe is too dam loud for everywhere i go and everything i do. with sound testing at local races now i have to get something new. i have a pro circuit ti-4 muffler that will bolt right on with no mods or anything. the exhaust is 4 inces longer and the core is 1/4 inch smaller.

i put it on, and man is it better now.

my question is what kinda power am i gonna loose running a smaller core like this? my guess is im gonna loose top end power and gain a bit more bottom end power due to the extra back pressure ill have. am i right?

please let me know

thanks.