from what i recall, the supersprint is one of the quietest aftermarket exhausts available. are the holes in the "suitcase" resonator? you can just replace that with a straight through y-pipe just like timevalve makes. the local meineke quoted me less than $200 to make one (not stainless steel). any decent muffler shop can fabricate that for you as well. as you found out, the original is one piece and they will have to cut the pipes no matter what component you replace. just beware that it is the rear muffler that does most of the sound baffling. if you remove the center muffler there will be only a slight difference. when you replace the rear muffler with an aftermarket one it can get pretty loud!
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"