Statistically speaking, GTR is not for you. This hardcore racing sim was built by a scattered team of hardcore racing fans and mod-makers who licensed an engine to build the game they wanted to play. The subject matter is a European circuit (most of the SimBin guys are concentrated in Sweden) in which highly tuned sports cars slathered in livery battle it out for a time-based race in which he who drives farthest wins. There are no fictional slices of New York City or some idyllic countryside or an alpine road with a strategically placed waterfall near the finish line. The tracks are the sorts of snaking affairs the French might love, forcing compromises between turning performance and straightaway power, and all re-created actual tracks. GTR's official licensing is even written in French: FIA stands for "Federation Internationale de l'Automobile." You should probably throw some accent agues in there for good measure.
For the Love of Speed
Like many developers laboring outside the control of large hungry publishers, SimBin enjoys the luxury of not really caring how much "game" it puts in its sim. There are very few concessions to the types of people who would find themselves hooked by Forza, much less the types of people who buy EA's brash Need for Speed games. From the get-go, you have all the cars, all the tracks, and all the classes dumped in your lap. There's no career progression and no sense of owning the cars. If you're looking for a reason to race beyond the simple desire to come in first place, you're in the wrong sim.
But if you're looking for one of the most gritty physics simulations this side of Papyrus' Grand Prix Legends, the last great game that developer made before succumbing to the commercial success of licensed branding, then GTR is a thrilling throwback. This is an overwhelmingly complex and sophisticated simulation of how a high-performance car behaves, how thoroughly you can tune it, and what bad things happen if you don't drive it right. It requires -- no, demands -- practice. There are no tutorials here. SimBin expects you're here because you already know this stuff, or because you're willing to put in the time to know as much about it as it does.
The Simpler Life
To be fair, you can scale the realism down. There are a number of driving aids, and an arcade league that caps your speed in favor of dumbing down the opposition. There are also various A.I. settings to keep the other cars from blowing past you. SimBin even created a downloadable set of the simple oval tracks NASCAR drivers prefer. If you don't want to read the in-game help for tuning your car (because the 11 pages of documentation certainly aren't going to do you any good), you can use a couple of canned set-ups for each car or go online to download other players' set-ups using an in-game browser. It all helps a bit, but it can cultivate bad habits, and it ultimately misses the point of the game which is to take advantage of the realism SimBin has provided. GTR is not competing with Forza.