Like all the other "Perfect" achievements in this game you have to get an Awesome aggression rating and a Gold medal in every event in the Dangerous rank. The guide below by L0Straniero91 has some excellent general tips, but I found the most difficult part of this achievement was getting a gold medal on the White Mountain Preview Lap so I thought I'd share some tips that enabled me to complete it.
There are two key things you need to be able to do to get the Gold on this track:
A. Drifting - While holding A & RT and beginning to turn, tap LT to start a drift. Some corners require a double or triple tap of LT to slow you down enough to corner without hitting the walls. Your speed through most of the corners shouldn't drop much below 180.
B. Take the shortest route to the finish - Not all of the shortcuts on this track are marked with the blue lights you're used to, so here's a quick breakdown (from memory) of the important stuff:
1. Shortly after the start of the race the road forks, take the left fork into the oncoming traffic. There were only two cars here for me, both in the left lane, but the road bends sharply near the start and you need to be in the left lane to turn without crashing. No need to drift here, just be aware of the cars.
2. When the road merges there's a shortcut ramp to left, take this.
3. Shortly after the ramp there's another shortcut ramp to the left, I found that a 1-tap drift was sufficient to get me into this.
4. You'll go through a tunnel and over a bridge. The tunnel has some bends in it but no need to drift. In the right hand lane of the bridge there's a jump, take it.
5. After the bridge you'll come to the first of the more difficult corners. Left (2 or 3-tap drift), Right (2-tap drift), into a tunnel (1-tap drift, Left) and (possibly) another Right.
6. You'll now be driving into the town. This part of the track has a shortcut that will save you a lot of time, but unfortunately it's unmarked. You'll be on a straight and see the yellow arrows indicating a corner at the end of the road. This is the third left turn on this road. You need to take the first (unmarked) one, which will take you down an alleyway and up a ramp. Hit the ramp straight on but be prepared to turn right in the air to go through another alleyway which will take you out into oncoming traffic.
7. Once through the town you'll begin your ascent back up the mountain. After a series of uphill corners (1, 2 and 3-tap drifts) you'll come to a tunnel with open sides. There is an optional shortcut to the left of this. Go around the next couple of easier corners and you'll be on the final straight. I hit the tunnel at about 1'44" and finished the course in 1'57" and change.
So there you have it. Hold A & RT throughout the entire race, don't crash and you'll be fine!