Earn Easy Money
Put in the invincibility cheat. Go to the junk yard and buy parts that are the same or better than the parts you have (ignore what the bar tells you). The dealer will give you a wad of cash, or make better parts cheap. Thesse parts are beaten up, so they sell for less. Place in an unfinished race, and go back to look at your parts. If you had the invincibility on, they will be like brand new! If you bought a part that was worse than the original, you can now buy back the original, but for less than you sold it to the dealer for !