Gold
Driving God: Hold at least 5 different top ten lap times in time trial mode for at least a week.
Drift King
The next big thing: Participate in 1000 online races and come in 1st place 90% of the time.
Been there, done that: Race every single car in the game on every single track.
Silver
Dream Garage: Own every car in the game.
Mr Le Mans: Win the 24hrs of Le Mans in a-spec mode.
King of The Green Hell: Win the 24hrs of Nurburgring.
Some say...: Beat all of the Stig's Top Gear Test Track lap times.
Bronze
Fast and Furious: Tune a stock road car that starts with less than 200hp to go 0-60 in less the 4 seconds.
Slingshot Engage: Draft an opponent for over a 1/4 mile and overtake him.
Houston We Have Lift Off: Get over 10 feet of air in a rally car.
Mr Clean: Use the car wash over 250 times.
All I can say is



Come on if collecting 700 or so cars isnt a gold, and 1000 online races win 90%

Race every single car on every single track
I like your names for the trophies, but it seriously needs to have the difficulty adjusted, but then again id put winning the lemans using soley the a-spec mode as a gold