I guess we are all different. I didn't buy this car to break any track/speed records as i don't really think it can with or without a sunroof. I didn't buy this car to be driven around as i can't afford a full time driver and its not that luxurious.
My thoughts have always been, "never buy a car you can't afford to maintain" base or premium. So whether I bought base or premium as long as I can afford maintenance on gauges, tires, brakes, transmission, engine and etc there should be no issue. When you're purchasing a luxury sports sedan it really all comes down to your independent choices, being an owner of BMW & Lexus, I decided I wanted the new Caddy CTS V Sport with its awesome LED driving lights and aggressive styling not because I needed one but because i wanted one and because I am in a position that allows me to indulge my wants i got it fully loaded. I'm not worried bout resale value, im not worried bout sticker price, im not worried about service, just as long as it does what i paid for and so far Cadillac has achieved to meet most of what it claims this car can do. If anything i believe as a luxury sports sedan it lacks in some departments. Motorized folding side view mirrors, motorized open/close trunk are 2 two on the top of my list I woulda loved to have.
Overall the car is an 8 out of 10. its great in comparison to other and it lacks in comparison to others. I enjoy it quite alot and when i stop enjoying it, i'll sell it, trade it in and move on to my next toy.