Need I just say an obvious? GT dosen't claim to be a simluator for nothing, they wanted to give hardcore GT fans, not to mention fans of RL GT races such as the ALMS and FIA GT, etc a true feel for timed endurance races. A lot of races both GT and other leauges can last a certain number of hours. It's also a test of 'endurance' as the name implies, in RL you have to worry about a lot more besides tires such as fuel, conditions of your parts, etc, but that's an obvious.
To put it shortly becuase I would take too long to state everything out, it's there for the hardcore fans and the curious as well as far as I know. They are tough but in a sense they're worth the time becuase you start to learn the limits of you car and also yourself as time wears on. It's an 'endurance' and be luckly it's 2 hours and not 24 hours like in Germany, Belgum, France, United states and any other place where they hold 24 hours races (Spa, Zolder, Le-Mans, Sebring, Daytona etc...), more or less. Then you would have to call for help of 2 or 3 more drivers.
To close, this topic reminds me of when me and my brother did our first endurance race in GT1, SSR11 enduro. We agreed to use the Mitsbushi FTO Le-Mans edition, we took times driving it every pitstop or so and it was fun.
That's enough pointless talk from me, till later.
Dummy 
COOL DUDE 
