You unlock this achievement after successfully completing Mental Block by hitting 135k and completing the track within the time limit.
I must have attempted this over 20 times, but finally nailed a method.
I recommend the Hurracan or Aventador. Personally I found the Hurracan superior around the second half of the track which has sharp turns, the Hurracan is able to quickly get the speed back up. Have the tuning set around half way along the drift bar. Anymore and your speed is reduced.
The best advice I can give is don't approach this track as a Drift event, approach it as a race. If you get to caught up in the score you won't make it. Focus on finishing the race, you'll find you will naturally rack up points. Also don't try and drift every corner.
Secondly, think of this as 2 races, a mountain race then a urban race. During the mountain section you will want to keep your speed as fast as possible, only attempt to drift the long U shaped corners.. Do not use your ebrake to drift at all, build your speed up then slam LT and maintain the drift. You should be looking to get at least 50k from the first 5 corners, they are perfect.
By the time you leave the mountains you'll want around 100k. As long as you are somewhere in that range then don't worry about the score now it's a race to the finish.
The second section of this race is urban, with Sharp angled corners. For these you need to Change your approach and now you should always use your E brake but nitro boost to keep your speed up.
This track is unforgiving I found myself always hitting the score but never reaching the end. As soon as I said screw the score In just going going to finish the track I hit it.
Like I say think of this mainly as a race and it takes a lot of pressure off