mikmaxx,
Both Slimline and Bisson make pitts style mufflers for a side and inverted tigre mount. I currently am flying an Ultimate with the 3250 inverted and using the Slimline which is a wraparound style. I do not have a Cline regulator installed but have not experienced the need for one. I am using muffler pressure and RedMax 5%Tigre blend fuel.
This motor was well broken in before I installed it inverted into this plane which does make a difference with the tigre's. All up weight is just over twelve pounds and hovers are great (NX 18-10prop). No monster pull out, but enough..