Mines Mystique
Weight is of course irrelevant in such a calculation. Crank and wp do not, I'm sure you are aware, rotate at same speed.

I can post exact size of impeller later today; I have 2 freshly shattered plastic ones, I'm just going to have to tape the bits together to measure but I think about 2.5". ( Edit: 3.0")

"We wouldn't sell metal ones if they couldn't withstand the centrifugal forces".. GMB

"We wouldn't install plastic ones if they couldn't withstand the heat".....Ford

Fictitious quotes of course, but who would you believe?

98 Mystique LS v6 atx 110,000km
97 Contour LX v6 atx 125,000km
stock CD on LS, cass on LX
spoiler, tinted windows on LS only
4 wheel discs on LX only
All other available options on both