Wider tires and narrower sidewalls—245/40s on standard 19-inch wheels versus 225/50s on standard 18s—are supposed to improve grip and increase feedback through the steering wheel. Stiffer front and rear springs and firmer dampers can keep the restyled TLX's body more composed. Finally, a thicker, larger-diameter rear sway bar should give the TLX more neutral handling and quicker turn-in.
Words like "should" and "can" are on purpose; I just couldn't notice a difference between the two setups on the road. There may be some empirical difference in a controlled environment, like a test track, but i drove it on twisty roads outside Louisville, Kentucky. I'd fail a Pepsi Challenge between the TLX and TLX A-Spec. The detailed specs agree: the numbers are so incremental year-over-year that only accountants and ants will notice.
While I can't really spot a difference in the A-Spec's handling versus the standard model, the same is mostly true of its ride comfort. Acura's sporty TLX feels nearly as comfortable on freeways and surface streets as the standard model. I say “nearly” because going to a larger wheel and skinnier sidewalls will always impact ride comfort. There's a little more road noise, but it's far from a deal breaker.
So no, the sport-tuned suspension on the Acura TLX A-Spec isn't a huge departure from stock—which is almost certainly true of its rivals, too—and yet, this is still a fun vehicle to fling around. The Acura isn't as sharp as a 3-Series, A4, C-Class, or IS, but it's also more forgiving.
And will any of this matter to the folks that snap up the A-Spec? Not in the least. The thicker grips on the steering wheel, the slightly flat-bottom-like shape, and small bits of extra bolstering in the seat create an enjoyable impression of sportiness even if the actual performance doesn't stack up. The TLX A-Spec isn't much more dynamically capable than the standard model, but it does a better job of putting its driver in the mood for fun.
The A-Spec's upgraded Active Sound Control is a big part of that. ASC hushes up the engine noise in Econ or Normal driving mode and allows more noise into the cabin in Sport and Sport +. Best of all, ASC doesn't sound artificial, like the Lexus IS 350. The A-Spec's singing voice is a reward to the ears, with a rich, sonorous V-6 engine intake note that makes aggressive driving even more entertaining.