I can't help but comment on this. I am not sure what you mean by "improve" on this car. It is a mix between a Bugatti and a SAAB. Are you saying that the ingame that they did a better job putting these two together than they did with the Rapid GT? If that is what you mean, then I can agree with that. I also dislike what they did with mixing the Camaro and Challenger. In fact let's just not add fuel to the fire and keep muscle cars out of this discussion
Rockstar can't make perfect replicas of real life cars without incurring numerous additional license fees. Given the game's already record breaking budget, I totally see where they're coming from. That said, they've done a damn good job of keeping most cars immediately recognizable, and have even improved the design of some cars IRL (e.g. Adder in game >> Bugatti IRL). Some cars (e.g. Rapid GT/Exemplar), sadly, have been made to look uglier than their IRL counterparts (Aston Martin DB9/Rapide).
Yeah, pretty much. I'm saying that by taking the best design elements from Veyron and Aero X, Rockstar has made the 'Adder' look better than either one in real life. I'm not a fan of Veyron's design - it looks like a slightly flattened VW Beetle with a stoned face (its headlights design = ugh). On the other side of the spectrum, Rapid GT/Exemplar look cross-eyed and terrible compared to the elegant Astons IRL, so that's the low point of Rockstars's design 'hybridization'. Gauntlet, as you've mentioned, is much in the same way, for me at least. Contrary to Adder, I'd either take a full-on Challenger, or a full-on Camaro, since their designs IRL, are great.
In any case, beauty is in the eye at the beholder. I, personally, love Cognoscenti and Vacca designs, and hate the Z-Type one, but I'm sure there are people who are the complete opposite.