Exhaust size for HP

i recently went from a 2.5 x to a 3" x pipe with ultraflows.currently its dumped and feels like someone is under the car tapping the floor with a rubber mallet.i did expect to lose some low end and gain a little up top ,but the results were not what i expected.it seemed to pick up power(not a huge amount mind you) everywhere in the rpm range.it also seems to rev faster and have sharper response.the down side is its loud.with a chambered muffler like brand F it would be down right painful lol.i have plans on running tail pipes with custom resonators im fabricating similar to the 273 hi-po design.it should make it more pleasant on longer drives.