Blimey, Jim, I bet that was interesting to drive! Probably like giving full throttle to a Scalextric car.
My mini couldn't take more than Stage 1, the three bearing crank wouldn't have lasted five minutes with anything better.
Mike, as our newish friend weetabixface says, lithium grease is the stuff. You can get it in a spray can (with a tube like WD40 for easy application), which'll last for ages. Just watch out for overspray when you use it, as the bishop said to the actress.
(The step up from bog standard 850 "power" to the stage one thrust was definitely noticeable. Well, it was starting from a pretty low base.)