One interesting part that caught my eye was this:
"
Yamauchi began to speak, first concerning the portable version of Gran Turismo, GTPSP. The first thing mentioned is that it was a challenge to develop something as big as a GT for a machine so small. They had to redesign many aspects of the game, and come up with new methodologies to take advantage of the technology of the handheld. It is this aspect highlighted in the ad-hoc mode in which the opponents play against each other in the same space, or Party, which can compete online with other gamers worldwide via a free application that is download on PS3.
He also said he was particularly proud that the modeling of the cars comes from the PlayStation 3 version and not previous versions. Clearly this aspect has been simplified so that PSP can represent them on screen, but thats the only change. All details are there, even the interiors"
This would seemingly answer the question regarding how the cars will look once we transfer them from GT PSP to GT5. We are basically looking at downgraded GT5 models (which explains the empty cockpit views) when we play GT PSP. Looks like I definately made a good decision get GT PSP