Mark,
I think the Fox Factory stuff or Wheel Smith upgrades are period correct Mods/Hop-ups that add value. These are the types of bikes I love! Moto-X Fox RM's and CR250's, Team DG bikes, LOP CR250's or an RM125C and Mugen bikes are the cream of the crop.
The 440 Maico would require an entire restore to get it back to a near "original" state. It is a real beauty for sure, but I just like bikes that are closer to the original or period correct, because when the s**t finally hits the fan those bikes will hold the most value, in my opinion.
Both are nice bikes, but the 440 owner added his personal touches to the bike and there is nothing wrong with doing that.