If you go with the GS, you will not be disappointed. As mentioned, it was Motor Trend car of the year when it was introduced, and the V8 version was as quick through the slalom as a Corvette that year, and had the second shortest stopping distance of any car they tested that year, after the 911 turbo. I have had the 6, and have the 8 ,and would recommend either. The 300 is not super quick, but certainly satisfying for many people. Of course step up to the 400/430, and you may be quite surprised at how fast this sedan is. I always wished a manual transmission was available, but otherwise a fantastic car, and as mentioned, insanely reliable, like not a single issue with either one.