All aftermarket/OEM chargepipes work with either option. I'd recommend going with the 2.5" connectors simply because it's less expensive and less restrictive. The factory connections shrink down to about 2" and will impede flow in the mid-high rpm range.
Any intercooler over 5" will require cutting (AMS, HPF, BT, ect) but the trimming that is required is minimal. Only 2" of material needs to be removed from the back of the black shroud (not the bumper) and only takes about 20-30 minutes.