Yes, that is an advantage.

However... also remember that GT4:Prologue was launched to a user base of over 14 million, instead of 1.4 million. It had almost exactly 10x the userbase of the PS3. Again, not saying it isn't possible... just not sure how important "PS3/HDTV" is in comparison to 1/10th the userbase. 

If you want me to put this succinctly, Sony is expecting GT4:P to sell at approximately 15x the speed as GT3:P did, when user bases are taken in to account. Possible, given that the current PS3 userbase is probably more hardcore and, as you said, doesn't have any Gran Turismo game yet, but still seems like a very steep climb. 

150-200k seems reasonable, hopefully it will do well in Japan.

I think this was Sony's 1st week expectations.

this game dose look good but the graphics arnt a big step up from forza 2 which is disapointing, should easily do 200k

I thought the game was free. I could've swore Sony said it was.

 no that was GTHD. None of the prologue games were ever free. they were ust cheap like $29 - $39

What have you been looking at GT HD?

I'm almost positive they mean 250K lifetime. I would be impressed if they get 150K first week, and sales shouldn't be sustained very long at all after that.

eh, i think this expectation is too high but whatever.

this is lifetime predictions. Not first week.