It was pretty good, but in 2016 Streetpass was used by little to none people so it was kinda hard to progress in the game. Never got to finish it, but I did like the concept (I'm a huge model car sucker tbh).
Long live StreetPass. One of the better games in this final wave of StreetPass DLC...slot car is a heck of a niche but I wish there were more like this.