PS3 Sim-Style Racing Games

I just sold my 360 and got a PS3, and while I am loving the hardware and games generally, I miss Forza.

What is the best "sim-style" racing game on the PS3?  By "sim-style", I mean that the following a racing line is important- nothing along the lines of NFS or Burnout or Motorstorm.  It doesn't sound fun, but I like doing time trial races over and over, hoping for the fastest time.  Listening in, I get the idea that Gran Turismo 5 is not the way to go, but I am still looking at it.

EDIT:  GT5 seems to be almost obsessed with being serious and hardcore and as realistic as possible.  Forza wasn't exactly a super happy game, but the liveries were fun and there were the Top-Gear challenges.

So far I see:

• Gran Turismo 5
• Shift 2: Unleashed
• Dirt 3
• F1 2012

Which of these would you recommend to a Forza fan now converted to Playstation?

What makes GT5 a better game than the others?

So far I see:

• Gran Turismo 5
• Shift 2: Unleashed
• Dirt 3
• F1 2012

realguitarhero5

That's pretty much it really.  There's also Ferrari Challeng:  Trofeo Pirelli, which isn't really too good, but it's fun enough to keep a sim fan entertained for a week or so.  There's also Project CARS coming out around Thanksgiving, which will hopefully be good.

Out of the ones you've listed my favorite by far was Shift 2:  Unleashed.  Although it does suffer from some arcadey oversteer, the selection of tracks is gigantic and the AI is pretty good.  The cars have very unique and subtle differences in their handling - I could spend a good half hour driving the same car around the same track before I felt like I was really running good laps with it.

GT5 is pretty good, the selection of tracks is downright lousy compared to Shift 2, but the physics are decent enough.  Vastly over-simplified and easy, but fun enough.  Its AI hasn't really advanced one bit since the PS2 days.

The F1 games are great, the physics are excellent and the AI is superb.  I played F1 2010 and it was extremely challenging, I'd spend 2 hours practicing on a track before I felt I was ready for a race. 

theres nascar

grid

nfs  shift series