I thought i would add my two cents on GT PSP. I have been a long time fan of the series, even from the PSX days, i've played through all GT's, and i'm eagerly waiting for GT PSP. I think the game looks awesome, better than almost all games on the PSP. I'm a realist as well, and there is no way that it can compete with the graphics of a 360 game like some of you suggest, but it can give most PS2 games a run for their money in the graphics department.
Here are some screenshots from GT4, compare them with GT PSP screenshots and you'll see that they don't differ much in graphics, and that is a huge asset for a portable console, being able to run as well as a home console.
Source : http://delobbo.com/gran_turismo_4_1.html
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
