to Reilsss: Maybe they planned the McLaren F1 Longtail as a racecar for Circuit spec. When you take a closer look at the trailer you can already spot 2 different frontends: standard F1 road car and F1 LM ground effects kit (guess this is for Perf spec).
BTW I think that with the new DLC plans the developers break their original spec concept.
Aston Martin V12 Zagato should be a Perf of the car it is based on rather than a standalone model. Same goes for the Ford Shelby Mustang GT500 (I know, not DLC related).
I would have thought of the following model tree:
Stock: Ford Mustang GT
Street: Boss 302 (balanced for road and track use)
Perf: Shelby GT500 (think of the Super Snake, perfect matching the definition of Perf spec: enormous accelaration and speed, therefore less control)
Also why did they chose the Mercedes SL63 AMG?
In my opinion The Crew's spec logic would look like this:
Stock: SL65 AMG or SL600
Perf: SL 65 AMG Black Series (look at the car in the bespoke trailer, you can clearly see a Perf spec SL63 AMG)
Now we have 3 AMG models with basically the same 6.3 litre engine. With the Pagani Huayra even a model for the AMG V12 already exists in The Crew. Okay it is highly modified but the base is the same and for the displacement the block simply could have been downscaled which is a lot easier in 3D than in the real world.
Do not get me wrong, I like how the carlist devoleped over the last months, but the mentoined models just do not match the originally claimed purpose of the spec system.
If you look at some already confirmed examples of cars in the game you can clearly see what I mean:
Lamborghini Murciélago
Stock: LP 640
Perf: LP 670-4 SV
Circuit: Murciélago R-GT
Nissan Skyline
Stock: R34 Skyline GT-R
Street: mostly Nismo inspired
Perf: aftermarket import custom
Circuit: JGTC racecar
MINI
Stock: MINI Cooper S
Street: MINI Cooper JCW (in mostly every other game the John Cooper Works would be a standalone model)
(I left out Dirt or Raid in this because they do not have real life counterparts)
Also I noticed in the DLC trailer that the McLaren MP4-12C has blue tail light casings. I think these should be black on a stock model. The showcased one could be a Perf spec (as we know on supercars this replaces the Street spec) but it is missing the jagged side panels (I really hope that the Perf spec cars will be available with stock fender panels and some subtle rear spoilers because on a lot of the shown cars the parts destroy the original flow of the lines).
Sorry for writing so much but I felt to share these thoughts with you guys.