I think the title covers it, I don't want every thing else, don't want to pay $99 for 2 dirt tracks and a few cars...
The Adrenaline Pack (Dirt) DLC will be sold separately from the season pass (season pass includes it, but it's not exclusively season pass bound) - no need to purchase the Season Pass for it - currently the Adrenaline Pack is still in development and not out yet.