I was just out to the field today for a couple of flights with my Sukhoi and the 2300. I've got the Bisson muffler and 5/32" fuel line installed. I had a couple of flights on the engine but I noticed that it now seemed that it wanted to be leaned out a little on the low side but could have been a hair richer on the top end. I decided to plug the one exhaust and see what that did for it. Doing that cured the lean high end. I plugged the one closest to the pressure nipple (if it makes a difference to anyone) and now it sounds great all the way up. I turned the low end in about a 1/4 turn until all was said and done. Now, it idles better, transitions better (quicker) and doesn't 4-stroke as badly at idle. It was new just a few tanks ago so I was sure it would need a little more tweaking as it broke in. It just keeps getting better! BTW, I'm still running the ST carb with a type-F plug and a 17X8 APC prop.