Don't get me wrong, I used to run a Kit Car club, so I have seen and built cars from the ground up. When you do that, there is no such thing as an upgrade really, it is your own work of art and of course engines get tuned to bits, the suspension is as trick as you want it, and the interior and paint colour(s) can be whatever you want.
Also, I think I only own one car that has not been modified, that being due to having to insure it for use in france for 6 months at a time. Only SAGA will do it, and they won't insure modified cars.
So, yes, I modify my cars, but always for a purpose. For instance, I knew I was going to be doing long distance, high speed, heavy towing with my D1 Anniversary, so I modified it purely for that. I only changed the ICE when the disc player went wrong.
So don't get me wrong, I am not against modifications at all. But 50?
I think the answer is that no two Minis built today are the same, and you cannot buy a Rolls Royce off the shelf. The manufacturers are letting us do it on their production line. And I can foresee the day when we will no longer be allowed to modify. (See France, Germany unless it is TUV approved, etc,etc, etc.) We are so lucky to still be able to do it. And good luck to all who do it. If making it look like a cross between a Christmas tree and a pimpmobile, then whatever, revel in it!