rctoymemories

Thanks dust75 - much appreciated

Just on the subject of mods and upgrades... having sold a lot over the years, collectors always want the original article. In as new condition as possible. And that's a general rule across all vintage toys of course.
In the case of the Golden Arrow, mint in box examples that are all original, will always be the most sought after and most valuable. The current value of a mint in box Golden Arrow is around the US$400-$500 mark. You may occasionally see one sell for less under auction, there are always blips. But $400-$500 are the highest precedents. New examples are pretty rare.

For a comparison of how rare: original new in box Tamiya Hornets are rare too (as are all vintage new in box RC kits). There are limited quantities left in the world of any classic R/C car from the 80s. But I would see about 7-8 new in box original Hornets come up on the market per year. Whereas I would see about 1-2 new in box Golden Arrows per year.

Used, but clean examples (with little wear) are more common. While old bashers are the most common

So if you just want to experiment, then modding a Golden Arrow is fine. But if you like having things "all original", OR you think you might sell one day, then I wouldn't go down that path (or just get two - one to preserve, one to mod etc)