I was running my Saito 72 in my Aresti, I had no problems other than first starts, its hard to get the fuel into the carb as its inverted. Use a refueling rig as this will stop fuel from flooding the carb as you fuel up. Be patient in tuning, needles will be set leaner than normal. Its not hard to run and engine inverted. I ran a 4C and 2C inverted and both were great but you need to be a little patient only.