RE: SMC C-max 40C lipo
I wouldn't even consider it. The Reedy 5000mah 35C (175amps) is only $110 and I'd trust them more over SMC. Not that SMC doesn't make ok batteries, I have one and it runs fine but I have to seriously doubt that it's 40C continuous.
Quite frankly, I can't see the average basher or racer needing anything over 150amps discharge at this time. Anything more than that and you're wasting money IMO. MAYBE the guys that are going for the land speed records at over 100mph.