I'd stay away from the Tower brand. While my Tower .46 had above average power, it was a pain in the !@@ to get running, keep running, and make stop running. On the flights that didn't end in a dead stick, it would NOT shut off, even if I plugged the carb with my thumb. Some gold RTV around the base of the carb helped some, but it was still a pain, and it seemed like I had to tune it up every few flights. My OS's on the other hand only need tuning when the weather conditions change drastically, which twice a year out here in San Diego.