You're comment regarding no such thing as a better engine in the DTS is incorrect. There are differences in available engines for the DTS. The base V8, Luxury I and II models have 275 HP and 295 lb-ft of torque but the performance model mentioned in this thread has 292 HP and 288 lb-ft of torque.Look on the driver's door for the original tire size. It will VERY CLEARLY state 17 or 18 inch wheels. If the tire size does not match the door panel, then the wheels are NOT original.
These is NO SUCH THING as a better performance engine on these cars. They ahh had the same de-tuned NorthStar (about 275HP), whereas my 2009 STS Platinum has a 320HP / 330 Torque RWD engine.
That fuel door is a mess. The driver's door does not look much better. The carper on the driver side needs top be replaced.
You're also incorrect about the STS engine, I had an 07 STS V8 which is how I immediately knew your comment was incorrect. The V8 STS has 320 hp and 315 lb-ft of torque not 330.