At my dealer’s suggestion when I first brought up the issue of a spare of some sort (soon after I purchased the car), they suggested I check back with them from time-to-time to see if Cadillac would offer a spare for this car. I followed their suggestion, and “checked-back” as recently as yesterday. I was told by the dealer’s parts manager that Cadillac still doesn’t offer a spare tire for this car, and likely never will. jsanders indicated that Cadillac has an option for a compact spare on the 2011 model. I’ll need to follow up on that, because the parts guy at Cadillac stated that they didn’t have a spare for the 2010 or 2011 models either. As far as the well in the truck, my suspicion, and it’s only that, is that the body designers didn’t talk with the drive-train engineers, so after the car was designed to accommodate a compact spare, the engineers decided that the car could not be driven with one, so the compressor was substituted, but the well in the trunk remains. Again, that’s only my guess. I’m trying to confirm whether or not such is truly the case that the car should not be driven with a compact spare due to handling and drive-train concerns.