u cannot just cut off the mufflers and clamp on new ones. welding is needed. exhaust shops don't charge too much to put on mufflers. you need a 2.25" inlet and a 2.25"-2.50" outlet depending if u get different tips or not.
even with a 2.25" inlet, the shop will have to put on a small adapter because the y piping is actually smaller than 2.25". we had to do this on mine