Very interesting! One thing to consider is that the older version of this engine is different from the new one and some information on the net is for the old version. The pattern flyiers also use a tuned pipe on the 2300 thus allowing them to run a slightly larger prop. If you don't run a tuned pipe, you don't need the 18X8. Although the 2300 will spin the 18X8 it will be slow to revup and may even add to the mid-range problems with the extra loading. If you want to peen the end of the Bisson pitts muffler you can easily make a clamp out of wood and use a vise to clamp the muffler and hammer the ends to reduce the size of the exhaust openin. Done this way the muffler looks stock except for the opening being smaller. It will give more back pressure and you will see little or no reduction in power. One thing do with this and other engines is to remove the backplante and flush out the particles left in there from the factory. I did this and removed a considerable amount of stuff.