Simraceway have some new liveries/updates to their 2012 Indycar today, and it's available for free test drive. I gave it a go and I must say I had a good bit of fun with it, it's really intuitive to drive.
I'm going to be honest, I wouldn't call it a realisic or 100% simulation, it is obvious that while it's a simulation it's clear with how easy and forgiving this car is to drive, the fact that you can get away with wheels on the grass occasionally, and some pretty crude braking, not to mention the sheer mechanical and aero grip on the car, the perfect balance.. Like I said, I wouldn't call this the ultimate attempt of simulation with the Indycar, but it's definitely very intuitive to drive and as a result great fun, you can really attack it.
I drove it around their (I'm assuming new) Cadwell Park circuit and it was fantastic, never driven the circuit before in a game and I must say I really love it.