Honestly, aside from the three screens and the fans, it doesn’t really gain much over what we already have. As already mentioned, they are using an inferior wheel/pedal setup on it, and most of the other stuff you could DIY pretty easily. Hell, I’ve already got the bass-shaker and headrest mounted speakers, and I’m sure my home theatre audio setup is at least as good as the Bose setup they are using (probably FAR better, actually).
With GTR2, Race '07 and others, there is also no need for an extra screen for the rearview mirrors. Not to mention you don’t need more than one PC to do the multiple screens.