I still have DiRT 3 on steam and love it, but these days have a hankering for engineering games. There's something deeply satisfying about building a car in stormwanks or garrymode and after all your legit tuning and design it finally just works.
I do wish there were some engineering games about building cars from basic blocks. Not like My Summer Car or Automation, just something that really is gmod but car-centric and models stuff like aerodynamics and friction/traction a little bit better. Or even just Geometa fixing some of the more bonkers design decisions towards land vehicles in their game.