It was a sim/game from the early 00's. I remember playing it to death, On-line only from what I remember and the title suggests. It was a mix of racing game and Sim City.
Memory is a bit sketchy but from what I remember you bought an old rust bucket and then raced against other players to win prize money to upgrade/replace your current set of wheels. Factory upgrades were available but also a thriving player driven list of options as well. Almost completely American Muscle and a really active community at 1 time. I remember the players tried to take it in the direction of the illegal racing/cruising scene and it could very well have become a sort of "Fast and Furious On-line" where the painters and modders could exhibit their cars in a virtual world but EA pulled the plug and from the death of MCO came the "Need for Speed" series.
Anyway... Enough reminiscing I was having a clear out of many of my old back up CD's and found I had at some time in the dim and distant past copied the sound track and still had it so spent a nostalgic few hours re acquainting myself with such classics as "A Groove Thang", "Racing For Pinks", "T Bird Whine", "Drag King" and "Back Seat Funk" to name just a few. It also includes the radio versions played during the actual game itself.
Probably of no interest to anyone but on the off chance there is someone out there who remembers it here's the music.