[quote name='CheapLikeAFox']They've worked out a lot of the bugs in online and other people have find solutions. Initially, I could not get into games but then Spoderman told me to try changing my DL region in Steam and it fixed it. Haven't had an issue since.[/QUOTE]
You had to use that fix when the game first came out, but they've added a LOT of patches and have supported the game a lot since then, so you shouldn't have to go through any workarounds to get the online MP to work.
The PC version of Sonic All-Stars Racing Transformed has the best support of any Sega port I've seen yet.