Of the categories of racing present in this game, Endurance was my most anticipated. However, after your quite impressive line-up of cars for the Touring category, I can't help but feel disappointed if those are all the cars you have in store for this discipline. Endurance racing is pretty big, has plenty of great cars and I think this list falls short of an appropriate representation of the category. Allow me to explain my opinion on this in more detail.
First, the Aston Zagato. A better choice could have been made here, namely the Vantage GT3. The Zagato in question isn't a GT3 car (there is a GT3 version but this isn't the one) and really shouldn't be racing together with the likes of the SLS and the R8, considering there is no multi-class racing in this game.
Second, as another user above me pointed out, the inclusions of the Mazda 787B and Lola B12, while nice, are a bit pointless without having anything to race against (remember, no multi-class in this game). The Mazda is a Group C car and the Lola is a modern LMP. Very different in performance. At the very least something like a Jaguar XJR-14 should have also been included, as well as something like the Oreca 03 or a Zytec.
Third, no LMP1? Would have been nice to see the Audi R18 E-tron and the Toyota TS030 racing against each other.
Those critiques being said, a plus point for the Super GT500 cars. Nice addition.