Update 6-2-2018: added link to the DLC and updated prices(Thanks Lucky!).
Yeah!! Got my Level 30 earlier today. Here's a method to get ~8000+ exp in less than 2 minutes of race time! You will need the Heroes and Villains DLC(£3.39/$4.99 on 6-2-2018), which adds new challenges, no achievements, but a fun DLC!http://marketplace.xbox.com/en-gb/Product/Heroes-Villains-Pl...
I think I got 8000 exp actually regularly. My last race to get the level 30 I messed up terribly, but up to then I was getting either 7000+ or 8000+ experience every time.
**I'm including a descriptive paragraph and a numbered solution description, take your pick :-) I'm sorry, no video capability, but I hope this works!!**
Rapid pass x11, all the exp comes to around 8,150 exp, including 500 for perfect run, 250 for all resets remaining, and 100 for silver medal.. about 8000 exp!
You need to find the Need for Speed Underground challenges playlist, and select the first race. You'll be racing across the Golden Gate bridge into San Fran. Now, don't pass any of the other cars, just build up your NOS as you cross the bridge, stay behind the cars all the way over the bridge, making sure you don't accidentally pass at the corner getting off the bridge!
Follow them around the exit ramp from the bridge, you'll go through a narrow corridor followed by a 90* left turn. There is the first short cut here(through parking lot) on the left. I took this short cut every time, but it might not be necessary. Just make sure you stay behind the 11th place!! Go through the short cut, and hit NOS when you're about 50-100 feet out of the shortcut. Start passing the racers on the right, make sure to start cornering early as you're going uphill and it's easy to run into the wall and wreck or lose speed here. Important!! As soon as you get over the hill, keep passing racers, but look for a chance to cut through to the left and cut the corner up ahead(90* left corner). Cut the corner, and if you did it right, you should now be suddenly in 1st place!! x11 rapid pass in your pocket! From here on, just stay on the left side, watch out for cars, and hit the final short cut to save a few seconds, but you shouldn't have to worry about anyone passing you. In fact, On a race when I messed up terribly, I was in 4th place following them on the last long straight stretch. All 3 cars in front of me hit the same edge of the cable car track barrier and spun out forcibly. LOL.
1. Make sure you have the Heroes and Villains DLC. If you do, great! If not, it's £3.39/$4.99 as of right now. Worth it though, has some great challenges that it adds and nice cars too!
2. Navigate to your challenges menu, select the "Underground" challenges list, and select the first race.
3. You have one choice of car....
4. Race starts! Follow the other cars over the bridge while building NOS and do NOT pass anyone yet.
5. Follow the racers off the bridge, and around the first 90* left turn.
6. Take the shortcut through the parking lot--be careful to not pass the racers on the regular route!
7. about 100 feet out of the shortcut, figure out what works for you, hit the NOS!
8. Start passing racers on the right side. It should be clear everytime.
9. As you come to the top of the hill, anticipate the slightly tricky gradual left turn.
10. Look for an opening and cut through the racing line to the left to be ready for the next 90* left corner.
11. Cut the corner sharply, about 100 feet before the corner, use the shortcut wide open corner to cut off racer #1 or quickly catch up with him.
12. Cruise to the finish on the left side of the track watching out for traffic.. optionally use the last shortcut but be careful to anticipate it!! Otherwise you'll hit a nasty corner.
13. Enjoy your 8000+ exp if you did it right! If you did it wrong, you probably got a minimum of 6000+ exp!
Questions, comments, critiques, please let me know!! :-)