Does Restoring an Item Ruin its Value?

[Super]

Yes, it would definitely affect the value if you are talking about any painting and/or decals/stickers. It would never come out like the special stickers used and the manufacturing paint and colored plastic as it was new. If you are talking about repairing the workings like motor, gear replacement and re-wiring, I would say it would not affect the value as long as the repairs were done very well.

This all being said, if your plans are to sell, I think it would be very important to list the restorations and/or repairs so any potential buyers would know exactly what they were getting and judge for themselves what the value is. If you are planning to sell on a site like Ebay...using the Auction and starting at a reasonable price might be the best way to go and let the market dictate the value.