A couple of details about the Infiniti and Mercedes, put them above the overall design of other cars.
Mazda nailed the front. Since it's based on the beautiful RX-Vision '15 concept, it's already established as a real car. The rear hips are a bit plain in GT3 guise, but it's a great job by Mazda. Not just because I love Mazdas, but seriously, I'd have it out of all the cars here. It's not all out there. It's elegant, sporty, aggressive standing still. Nearly understated in this bunch.
In my opinion, the only flaw to me, in the Jag... the side "windows". The slits ruin the look of not following the side door ascending curve. On the flip side, if Jag did make a full window, the greenhouse would look just like all the other cars. Other than that, it's an elegant shape and definitely shows Jaguar's racing heritage. Looks expensive to booit.
The Toyotas. I placed both in because we can see Toyota gave the race car a more aggressive face. They pinched it more to raise the front fenders. The F1 type nose is pointier. Overall, it's almost Rocket Bunny-like.
The road car concept, of course has been developed into the Supra. This design is more favorable to the masses than the A90. FT-1 is closer to the LFA than the Supra is closer to the 86. This car was really designed well. Loys of sculpting and some nice details.
Back to the Infiniti and Mercedes. Biggest detail is that rear of the Infiniti. Looks incredible. The overall shape would appear fresh 10 years from now. The side skirts detail/sculpting is sweet. Very nice car.
Mercedes put a trick grille on their cars. They've almost gone the 300SL route. A design that'll hold up with time. When I first saw it, very soft curves. Even the wheels have that soft flow. They finished off the rear with the light bar. It works. Mercedes like that one-piece-carved-out-of-granite look. The blending of the aero parts. make me recall it.
I can't call who did it better. Good job by them all.