I normally use 30% from powermaster because thats what my LHS carries but now they got some 40% odonnel and I already bought it so what can I expect from going from 30% to 40%. Also how good is this engine I am planning on using it in my new NRS-RR12L5. Or should I stick with the 30% I havent opened it yet so I can always change it.

stick with 30% unless you are a master tuner that can tune that motor to run with 40%, also your engine life will decrease with the 40 %.

Not exactly true. You'll find that from the switch your engine response will change quite a bit, it'll feel a lot more like an 1/8th scale. It's really addicting . my TSR3 runs at a cool 200 and is dangerously fast on the bottom. You might need to change the head shim.

i think just from the switch from powermaster to odonell will make a difference, imo mugen/byron is the best and trinity is second