The only problem i can think of in merging console and PC times in one category is graphics. On PC grass can be fully turned off and it gives a big advantage because all bumps and small cuts become visible. This can definitely be dealt with, but i thought i should mention it here.

Another thing is FPS difference. Codemasters F1 games (22 and prior) are known to process car physics differently depending on the FPS. Of course, they run on much newer version of the EGO engine, but we have no certain proof that this bug doesn't affect older games like DiRT2 or DiRT 3. I have both PC and PS3 versions of the game, so i might test it in the future. Just a speculation on my part.

Yep, i agree

There's a cut at 1:20 (1:15 run time), you can cut the corner by going through the trees, but I think there's no time gain by doing it. You lose all momentum and need to gain a lot of it back, so no advantage there imo.

I think -1.5-2s is possible w/o new cuts if run perfectly through all chicanes. In-game leaderboard shows high 1:42s so lots of time is still on the table.