looks like they will fit with a bit of adjustment
this guy on ebay has done one
Auspuff Porsche 356 912 Sebring Peashooter super Sound on eBay (end time 17-Jan-10 21:55:09 GMT)
dont think i would be running that muffler set up though
was thinking of a A1 muffler mod'ed to come out the standard hole in the rear bumper