Well, I've spent a bit more time on the game now. I traded R Racing in on it, and although I normally hate dropping money on games, this is one instance I'm happy to make an exception.
I should point out that these comments relate to the PC version of the game.
The game has several modes, which basically boil down to career mode, time trial mode, custom race mode and on-line.
The career mode has has a really good makeover, and now takes place in first person - you're the central character, and all the cut scenes take place from a first person perspective. You have a Scottish team manager whose accent is strong enough to sometimes make comments made over the radio incomprehensible. It's actually quite tolerable, and a significant improvement. My only beef is that the career mode is the key to unlocking cars and tracks for time trial and custom race mode, although once unlocked you do have access to the cars prior to a race series to allow tuning.
I'm only partway through the career mode, and so have not unlocked significant numbers of cars - I'll post more on these as I go through them. The Australian version of the game has the V8 Supercars unlocked, and they are quite difficult to drive - but because of weight and sheer torque, not because of a poor physics model. An early highlight is the Formula Ford cars - they're nimble, fairly easy to drive and a lot of fun.
The steering and physics are so improved over the old game, it's staggering. Cars don't lurch or react violently on turn in, steering is direct, and the force-feedback is on a par with Colin McRae 2, which I rate as having the best FFB on a PC game (don't know if it's quite up to GT3 standards - we'll see). As mentioned, support has been provided for 900 degree steering wheels through a tweak in the .ini file - check the game's readme file for details.
There are two handling modes - Simulation and Pro-Simulation. I've been playing Simulation - Pro-Simulation is very difficult, and driving mistakes are severely punished. Might build up to that, I think!
Graphics are very good, particularly reflections. The damage is much more realistic - it takes harder hits to inflict major damage, and the mechanical ramifications seem to be better worked out.
There's quite a few nice little touches - things like the best lap time coming up about ten seconds before you cross the line, and disappearing again after ten seconds.
One annoying thing is the lack of splits and gaps - although your manager will comment if the gap's 5 or 10 seconds.
Seriously, this makes the first TOCA Race Driver game feel like beta version. This will more than keep me busy before GT4.