Motorcycle Club

For this trophy you'll need to earn at least 400,000 stunt points in one race. This may sound like a lot but you can rack up points quite quickly and easily if you can get a good multiplier going. The best track is one that you feel comfortable with and preferably has a good mix of ramps, rings, and straights for wheelies, close calls and top speed points. Also, the best bike for points is the custom bike, since it goes slower so is easier to control, and awards easy top speed stunt points. Try not to hit anything as doing so will be the biggest detriment to your points tally.

A sure fire way if you are struggling is the Kotoma Port track, this has a nice section near the end with a series of 4 ramps and rings. If you can use the custom bike to approach this and already have a top speed streak going, followed by jumping over all these then doing a close call or wheelie directly afterwards, you will rack points up quickly on each lap. Maintain close calls and a wheelie up the hill to the next set of ramps if you do miss a couple or ramp / ring combos.

With all that said, this is potentially a trophy that you will achieve naturally, and will not be any problem in the end. The hardest part is contending with the game's poor controls.

I was able to unlock this trophy online too on a second account.