Degrading your car...how?

[jemc]

ok, i've read a lot of posts on other forums saying that you make more money if you degrade the car to stock first and get the money for the parts and then sell the car for the price you got it for. i'm currently #10 in the black list and am driving Chevrolet Cobalt SS. i just bought Porsche Cayman and 30k won't be enough to upgrade my Cayman to the max (i have no luck with pink slips, btw). and i know there's more than 50k worth of parts in my Cobalt and i can only sell it for 13k.

anyone care to enlighten me?