Thanks to a combination of snow and ego, I've managed to damage the rear passenger-side wheel to the point where it won't hold air anymore. New wheels and a set of replacement rear tires (to compliment the new front ones) are being considered. Current front-runners: Rota Subzero 17"x7.5", and ADR/RS Concept Pro 17"x7" (with the same Sumitomo tires I have on the front), which are both under 17 lbs, a significant win over the stock 25 lbs wheels that came with the car (and, as I've so aptly demonstrated, are made of a semi-solid combination of lead and butter). Stay tuned.