I love to play Colin McRae DiRT with the G25 but it's impossible.
When I steer left, the game is a fricking second after! Which means, impossible to play.
Anyone knows how to fix it or is it because it's an arcade game? ...

Two things here.

First of all, are you using the external view? Because if so then that's your problem - the wheels might be turning but the car itself won't move until it gains traction.

The other suggestion is that it's an arcade game and is designed for joypads. Even then I hated the way Dirt 1 and Grid handle when I played the demos. I want consistent feel, not flipping between oversteer and understeer depending on my position relative to the corner.

I'm using view from the inside, that is I see the cockpit etc etc.
And I love the game, but the game is so arcade that it's impossible to play ...

Although it seems somewhat sacreligious with a G25, try taking the rotaion down to 360 degrees or so - it helps a lot with arcade-type games where precision isn't as important, but madly sawing at the wheel is.

I seem to recall having the same problem with the PC demo, and possibly the Xbox demo as well. When I rented the full Xbox version it worked fine. I never found a fix.

is your tv real big? cause it might be control lag.

DIRT 1 or 2?

because in DIRT 1 I had the same problem em various computers, operational systems etc, I have a DFP and ALWAYS in DIRT 1 the wheel have delay