If you're like me then you're kind of horrible at this game and driving a powerful car like a track toy just makes things worse. I tried some of the track toy events and failed to even get a bronze medal more than half the time. You need to get GOLDS to get this one. I found out a super nice and easy way to complete this challenge, however, and here's how I did it:As mentioned elsewhere, grab one of these cars
Caterham Superlight R500
KTM X-Bow R
Lotus Exige S
Ariel Atom 500 V8
(If you're not certain which cars are track toys you can go in to career mode, and there's the the Track Toys and Ultimate Track Toys events in the Specialized Career League. Grab a car that's eligible for one of those events and you're good to go.)
Now from the main menu go to "Free-Play
", change the race type to DRAG
, select a 1/4 mile track
, and choose your Track Toy car to start the race. You'll be up against yourself the whole time, so you're guaranteed a gold medal.
After every race hit the restart button. Do this 25 times for the achievement. Also note the race itself took 10 seconds, but the post-race screens and load screens took the longest to get through, so you're looking at probably a half hour to an hour to pop the challenge, depending on how vigilant you are at advancing the screens.
Also, the exp and credits earned doing this is quite pitiful, but I did end up gaining 1 player and 1 affinity level doing this, so that'll help a little.
You could also try double dipping with this challenge here, by participating in tag hoppers: