I would hope that the reason somebody modified their car, it would be because it made the car more like he wanted it rather than some hope of making it more valuable.
At the first LOG I took my car to (not on a trailer), I won third place in the "people's choice concours." There were several very nice examples of TCs and TCSs but I humbly thought mine was nicer than that third place would imply. For the next LOG I polished everything I could: header tank, the oil tank, the stainless steel headers, etc. In short, my car looked about as it ever did. I got another third place in the "people's choice concous" again! In frustration, I wondered what I would have to do to win or at least do better than third! After a few minutes, I figured that whatever it would take, I didn't want to do it. I had built my car the way I wanted it! After that, it no longer bothered me how it might be viewed. I will be completely happy if I don't even get a third at the next LOG.