Here is the full list of all 11 HTR+ Slot Car Simulation trophies - there are 6 bronze, 4 silver and 1 gold.
Win the first track on the championship mode
Complete the novice championship on normal or hard dificulty
Complete the advanced championship on normal or hard dificulty
Complete the pro championship on normal or hard dificulty
Complete all championship and extra tracks on normal or hard dificulty
Unlock all items in the Garage
Build 5 tracks closed in Track Editor
Build 20 tracks closed in Track Editor
Beat the Fastest Track Time of any Championship Race in Ghost Mode
Beat the Fastest Track Time of any Championship Race in Ghost Mode 7 times
Beat the Fastest Track Time of any Championship Race in Ghost Mode 14 times