Like a dream, It feels like I have twice the power. (than stock) When you floor it, it takes off sideways. Excellent compression. Starts easy runs smooth. It has a thermal shut off built into the carb, so no overheating. Easy on glow plugs, I've run 7/8ths of a gallon on the original glow plug. I noticed because of the size of the carb the throttle tree was preventing the the throttle from opening completely. I've fixed it, can't wait to see what it can do fully opened. JUst an example of how much power this engine has. I put HPI's Goliath tires 178x97mm on Blast wheels. There huge, with a 49t spur and a 18t clutchbell. It still pulls massive wheelies.
I've never had a STS 30, but I can say that I have no complaints about the OS30VG. More power than you'll ever need.
Thanks to all for the help, I'll try some of those methods mentioned. Next Question. What can I use as a brake piston, I lost my spare, and I really do not feel like buying a new brake kit just for the piston. Peace.