Ah ok. Any idea if they plan on adding to the game or is in a mostly finished state? Seems like there's a lot of ways they could add depth and that's my biggest issue now is that it seems like a very simple game for $20. That's not to say it can't be fun, I like plenty of simple games.
Oh also did they get the online stuff worked out? One of the Ars articles mentioned the online was pretty much outright broken on release.
The cars do have different hit boxes, but otherwise perform the same.
They will be adding maps and other dlc to it in the somewhat near future, although they have claimed many times nothing will be a paid 'powerup', so expect mostly cosmetic changes and cars in the future. However, they have stated new maps will be free. Currently there is a large patch in the works then some dlc coming out (I know there's a new car, dunno if a new map will make it or not). Devs have been pretty communicative on twitter and other mediums.
Server stuff has been worked out for awhile now, although they are still working on it. The initial load clearly overwhelmed them but also they had some rather unfortunate database issues at the same time. It took them a few days, but its been fine for me for awhile now. I played in beta and it worked great, so they had it down then but the numbers apparently far exceeded anyone's estimate and it would be nice if ars edits their article to reflect that (by the time that review came out the big issues had already been resolved).
I actually play this on ps4 since it was a free game of the month, and would consider a controller fairly necessary for this game (as for most driving games).
It's a great game thats lots of fun, plus a pretty good party game! Also it seems to encapture all kinds of people, gamers and non-gamers (gf loves it).