I've been doing a lot of game driving lately. I think you need to figure out what you are looking for: a racing simulator or a driving simulator? The driving simulator category would be solely occupied by Gran Turismo. The racing simulator category would include Race'07, FIA GTR, rFactor, Live for Speed, etc. The difference between a driving simulator and a racing simulator is that the former is targeted at the driving enthusiast, while the latter is generally for competitive gamers.
Racing sims will interpret your interactive experience as a sequence of mathematics. Got a Formula One car and want to take it out to a track for a race and tune? You've got it. Live for Speed will even render suspension loads illustratively in real time.
The driving simulator is for the absolute motoring purist for whom driving is a
severe passion. Want to drive your NA8C-generation Mazda Roadster through a twisty, cliffside forest backroad and feel the car's weight against the road through the front and rear double-wishbone suspension? You've got Gran Turismo. Driving simulators do not reduce your driving experience to a series of equations; they strive to emulate the feel and sensation of driving the car to the highest degree of realism. Unfortunately, there is nothing for the PC that is similar to Gran Turismo, although the racing sim titles out there are still passable as a somewhat genuine driving experience while remaining accessible to beginner and amateur demographics.
My recommendation is definitely Race'07 + GTR Evolution expansion pack. Exceptional game with great driving for all levels experience with a variety of automobiles. The GTR Evolution expansion adds the world-famous Nuerburgeing Nordschleife and its sister grand prix circuit, as well as a garage of mostly very high-spec GT (FIA "gran turismo" class) race cars. rFactor is another title that relies almost entirely on its third-party community modifications--the sheer count of mods is almost ceaseless. However, because it is so mod-driven, the game's quality and value depends on the execution of the community mods, which are usually poor or are difficult to configure.
For all games, I recommend a wheel and pedal set to make your investment of time and money worthwhile; I use the Fanatec 911 Turbo, which will cost you $450 after currency conversion, shipping, and Canada's infamous import tariffs. On the flipside, the Logitech G25 is an entry-level three-pedal package
for a decent price and is suitable for these types of games.