ORIGINAL: BootCamp

I try to play a demo before I buy anything. Couldn't get NFS2 Carbon to run on my computer.

Honestly, as much fun as racing games are, they're not much like a simulation.
With a NASCAR simulation, you have to set up every tire pressure, spring rate/weight, shock rebound, shock compression, toe in/out, camber, caster, steering ratio, track bar diameter and height, ride height, spoiler angle (front and back), gearing, tape on the grille, weight distribution (front to rear) and transfer (wedge), spring rubbers (size and presence)....everything that a real NASCAR team adjusts on a real car. After it's all tested and you have a setup that's fast and you can drive well (in traffic), you need to keep an eye on tire wear and temperatures, engine water and oil temps, repair damage on pit stops....... just like the real deal.
Then you have to use pit strategy to keep yourself in contention. It's very realistic.

I'm not slamming racing games. I enjoy playing them myself. But a simulation is a different critter - especially against real opponents who've been working on their cars all week and are trying to beat you and everyone else.