no supersprint here, mt holly. but I am in willingboro...hello, fellow south jersey e-30 enthusiast. I just had to weld my stock system, it cracked going into the cat. I did some research before tho, to look at sport exhaust, and they are few and far between for our cars, and crazy expensive when you find one.
My idea, and I will still probably do it at some point, is buy a universal resonator, some sort of sport muffler, the supersprints are nice but pricey, then get a muffler shop to make the pipe. There s a guy in Haddon that calls his shop mufflermania that will make up pipes and exhaust systems to your spec if you like, and he is pretty reasonable, and will either get you parts or install the parts you bring him. good luck,
Geoff