Continue playing NFS Most Wanted the way you do but:

when you try to get a pink slip, if u get it on the first try, get a performence marker as ur second choice

save up money for a porcshe carrera GT (280,000-only available after ronnie)
and upgrade it to max and give it all the performance markers u got using the above cheat

Porche carrera gt is fastest car in game

Money Maker Speedtrap: get money fast
on bull-the speed trap that is 11 miles and is mostly on the highway-it is worth 20,000 everytime u beet it- its eesy cuz its on the hihway and its a speed trap