To expand on my comment, I have been in the modified car game for a very long time. Selling a modified car is very tricky and usually does not bring in any money, and sometimes the car can be actually worth LESS. The only time it is worth more is if you can find someone who wants the car exactly as it has been modified. For example, someone could build a full drag race Mustang, and I would have no interest whatsoever. But someone could build a SN95, 94-98 with a fill Maximum Motorsports or Griggs Racing suspension and I would pay a premium.