They never made a two door CTS. You may be thinking of the XLR? They made a sporty version and a regular version.
IMO, the new CTS is not quite a BMW yet. The one I had (which I only got to keep a week) was the base model, non direct injection engine. Exterior styling is nice, but the driving experience was merely OK. The base engine lacks torque, though it does pick up a bit towards higher RPM. Interior design is fresh, I do like the Cadillac materials...approaching MB quality in some areas. Its a quiet car, rides well, and decent fuel economy....a very competent commuter with some grand touring capability.
The thing with the CTS is that it feels like a car designed by a clinic. It was made to be broadly appealing, but in a distinctly sanitized way. I suppose for the non-enthusiast it is perfectly acceptable...but coming from the GTO, I'm not sure this was the best choice for the OP. Any reasons why the 300C SRT8 was not considered?