I am a car guy - period. Over 44 driving years I have owned every model of Porshe (excluding Panamera) every series BMW including the M's, 5 Vettes and a few others I've built. The Sport GTS takes a few miles to learn to drive, and appreciate, but in Sport Mode, Manual shift using paddles it is absolutely excellent in every aspect. Handling - bearing in mind it is a 4400 lb car - is every bit as good if not better than my EX 2011 M3 with competition package, much smoother on corners than any Vette. and definitely not lacking on power. Granted it does not have all the stupid stuff no reasonable person would want (as offered with S550 or 7 series). But talk about attention getting. Wow!
It is very the most beautiful car on the road, still! Definitely buy the 2010-2012 years Quattroporte-S with the 4.7. Talk to the dealer mechanics and the sales pros, the 4.7 engine is bullet proof. It drives and handles way better than either a Jag XJ or Mercedes E550 or S series. Truly fun to drive and you can get 22 mpg at 75 mph on long hauls. There is no need to dog it in sport mode, why? From 40 mph to 120 mph+, the car is really quick in normal mode. I bought my 2011 in July 2016 with 12k miles and have put 9k trouble free miles, I choose to change the oil every 6k miles and use a German synthetic called Liqimali, my exotic repair specialist recommends it, better than American synthetics. Every time we take this car on a trip we always get horns honking, thumbs up, and people want to know what it is, most incredible car I have ever owned. Very satisfied.