Endurance mid-race game saves have been discussed before on GTPlanet and a lot of people, myself included, assumed PD would have taken note and included them in GT5 so I'm completely baffled that they haven't. The option to save your progress between races in championships, that was available in GT4, has also been omitted further restricting the game to people who don't have unlimited gaming time. To make matters worse you can't pause or speed up time in B-spec and unless you use a grossly overpowered car your driver needs constant attention to have a chance of winning the race.
Kazunori had said in interviews prior to the release of GT5 that gamers have changed and don't necessarily have as much time to play so GT5 would be different than previous games to accommodate this. Understandably people thought this meant GT5 would be aimed more at casual gamers and that it would be easier to progress but the lack of endurance mid-race saves and the other points I've highlighted mean that there will be large parts of GT5 that are unusable to a lot of people who aren't able to play for extended periods and don't want to leave their PS3 running for days on end. It's not just the worry of damage to the PS3 but also the restriction of using it for other purposes that make this option unappealing.
The latest information on the Gran-Turismo.com site regarding B-spec has a section titled
"Play to Match Your Lifestyle" which seems to be at odds with how the game has actually been designed. I'm not trying to infer that GT5 should be easy or quick to complete or that skilled players shouldn't be rewarded but it's unrealistic to expect anyone to have to complete very long events non-stop and it's unfair for people who simply don't have time to do it. The bottom line for me is that GT5 is a game which I have paid for and due to a couple of omissions that I'm sure would be easy to implement I won't be able to access a large part of the game. You could argue that people who don't have the time to complete long events should just not do them but it's content that has been paid for so why shouldn't they be able to use it?