I have never used opti 2. Thought about it a lot, but cant afford it since im not working. I do personally believe that it is ok for small engines. of course it wont work in a motorcycle engine, because its simply not designed for high rpm use. thats what they make opti max for. however, our engines are no motorcycle engines. in truth, these engines do not produce many more rpms than the "garden equipment" that opti 2 was actually designed for. lawn mowers, chain saws, weedwackers, leaf blowers, all are within the same performance range as a stock HT engine. so, opti 2 should work fine for our engines.