For what its worth, I have a Cherokee with a 46AX and the Bisson Pitts muffler. It fit my cherokee perfectly with no modification required at all. I dont know how it compares to the slimline muffler dimensionally, but if Ken tried the slim line and it didn't fit, and my bisson does with all other variables being the same, maybe the bisson will work for you.

http://www3.towerhobbies.com/cgi-bin...&I=LX8680&P=ML