Need for Speed ProStreet

To make your cars faster, buy a better one. For example, ditch the Audi Quattro TT for a Corvette C6. Or, simply upgrade your vehicle by buying parts for it and increasing the aerodynamics, among other things. Also, just try not to crash during races and you'll win every single grip/sector/speed race easily. Good luck!

To get a free marker, you need to win it in the chance cards that you can choose from when you win/dominate a race day. also, you need to be quite far into the game map to have them appear, but they are random. a tip, when you get one, buy a zonda with it, sell it and buy 2 ford gts and use 1 for speed and 1 for grip, really helps me with my teqnique.

Just keep doing the Drag King race and checking the markers.
You get easy cash fast, and since its a final race, the chance for lvl 4/free car markers is the highest it will go.