I'll second Sean's comment--especially with regard to soft change. I had a pair of ProAc RS2s on Target RS4 stands (filled with sand) and the four spikes on each Target punched through the pennies I used in no time. Wasn't even that heavy... Figure 75 lbs for the stand, mebbe 30 lbs for the speaker, 25 lbs of sand for 130 lbs total distributed over 4 spikes is, er... about 32 lbs per spike. With a sharp spike tho', the pressure on the point gets *big* very fast.
