[Tr6]

Modded vehicles will add a couple grand over the "blue book" value of a car but not to a dealership, to the right private buyer and depending on what all you have added. Aftermarket wheels, cosmetic stuff usually people don't care. If you tell them the car used to be 455hp but now is 700, that is much much more important that wheels and even then most will walk away hearing that and the word "modded" but if you find THE right buyer... You may just get some money back which is still laughable compared to what you have actually put in. I have sold both my evos (modded as hell) privately over 5k the "kbb" value. Now, I did dump 20-30k into both evos... So in the grand scheme of things, you won't get jack out of modding lol.

Glen's suggestion just might work for you to see it in person but you can always try autotrader or cars dot com. Any used car search engine really, for example: Just search a 2010 corvette supercharged and compare the price of that to a non supercharged one. There will be some difference but 2/10th of the price the guy spent on his vette lol.

Cars are all depreciating assets, you will never ever keep good value let alone make money on it unless... It's a very very special / "collectors" cars. #1 vins, uber old and rare cars etc.