Couple more details to help anyone rushing into this 1pt gamerscore (useful to roundup)
If you start the game with Asia region cars, you get a starting discount 5% plus the first Hyundai required for this for free!
Then at level 10 you get 30% discount on Asian Cars (less discount at lower levels, higher at higher levels)
Level 15, gets 35% discount, for example.
I managed to grab the Proto at 82,950 CR at level 11
If you choose races that give you more cash as you advance, it will be easier.
Also, if you're a good player, raise that difficulty so you can get there faster!