No worries, Ray. Although, the article really didn't have a lot to say that we didn't already know, I think.
I totally agree with Jeff - I wouldn't be too keen on heavily modding a desirable model (such as a Boss 351, 429 SCJ Mach 1, etc.) that had enough intrinsic value as a collector car. By the same token, I would also not make my car something it is not - for instance, if it were a 6-cylinder sportsroof, I would not simply toss on all the goodies required to make it a Mach 1 (short of the VIN) and try to pass it off as such.
It also [for me] would depend on how complete and what condition the car was in when I bought it as to how far and crazy I would go with the mods. I had a chance shortly after I bought my rusty pile/seized up H-Code to buy a pristine, faithfully restored, 90+ point MCA M-Code 1971 Mach 1. It was gorgeous and almost perfect! It was also only $24,500... which several months later dropped to $20,500. I should've bought that car, but I didn't because I didn't think I would be spending that much money on mine to get it back together (HA!!!), and with my intentions for my car I simply could not bring myself to mod such a fine specimen. I would've had to dump my pile as well, since I couldn't justify having 2 of them. It would've become a Garage/Trailer/Parade Queen, and that's just no fun in my book.
Having said that, my H-Code is now restored and still "numbers matching," with the exception of having an AOD rather than the stock FMX (which is in my garage, anyway). There are some mods that I can't [easily] undo, such as: sub-frame connectors, relocated seat platforms, deleted radio antenna, and some performance upgrades that could be turned back to stock if necessary (I kept all my 2V engine stuff, in addition to anything else that I replaced, even though it'll never get used). Most of my other mods are the usual basic things like upgraded stereo, rims & tires, louvers, engine performance goodies, etc., which all cosmetic things are "period correct," meaning the car 'looks' like a restomod from back in the day. The other things are things you can't see or would easily overlook, like aftermarket power windows, power locks, the roll-down quarter window mod, sport seat upholstery, cut-pile carpet, back-up camera/rear view monitor, and the upgraded stereo is actually a Retrosound unit which looks OEM, but has modern guts.
Now - did I increase its value or take away from it with the mods I chose? According to the gist of the article, it depends on the buyer.
I think it boils down to if the seller is in the market for a project, a driver, or a collector - values going up with each category... unless you're on the level with the Ring Brothers, or similar that is.