I agree with above statements. I would update engine/drivetrain/suspension but keep all original components for sale with car in future. Keep paint/decal scheme but try to score some 15" ssiii wheels to roll on, again keeping the originals, or did 442's have 15" stock? I don't remember....
IMO, many things could/should be done to increase driving pleasure but all mods should be reversible simply because it is a rare car and should you wish to sell it, your customer base is increased to include people seeking 'all original'
this is absolutely the right advice in my opinion. Do whatever you want, just make sure you can go back (or at least the new owner can go back).
I don't get the "waste" of money part. Sometimes people act like the majority of the money they spend on life is invested...like they don't spend thousands on alcohol, smoking, trips, parties, etc... and they lose 100% of that money with no tangible thing to show for it.