This is much easier than you think. All you have to do is buy a lamborghini murcielago. Then buy all of the upgrades and your lamborgini is ready for tier 3. This works just about all tier 3 cars. Good Luck!
OK, so what you need to do is win the 1st place in the beggining race. Get all 40k, then when you go get the cars, get the BMW as Tier 1. Later when you want Tier 2 car, BUY THE BMW M3 E92! It's the best Tier 2 car, well the most worth the mone at least. 80k is the price. What you do is test it out with no upgrades. If you like it, keep it and sell the Tier 1 BMW. You can sell it for the full price you bought it for! So that would be $35,000 leftover for upgrades. I upgraded the HANDLING first, it tunrd good(under AERODYNAMICS). Then upgrade the SPEED, and then do the last one. I am doing that, and it worked out for me!!!!!