The CS-130D differs greatly from the CS-130 - not only in appearance, but the mounting system.
The CS-130 is a 2-point mounting and can easily be configured into the 12 & 6 O-clock mounting style our vehicles use - the CS-130D is a 3-point system and has a different lower mount spacing.
Spacing shown here -
The CS-130 has all internal electrical components - the CS-130D has the electrical stuff hung 'outside' on the rear under a plastic cap. Maybe easier to service, but looks odd and doesn't like headers ...
The "D" has a heat issue - which was solved with the newer AD series by increasing the air flow over the rear electrical components.
I still prefer a 10/12 SI or a CS-130/144 over the "D".
I've only seen a couple of the AD series, but intend to do some investigating of them for retro applications sometime in the future.
The newer series of alternators are able to withstand higher RPM's than the older units ...
I find a lot of Alternators at the 'pick-it-yourself' spots for good prices.
If I need one quickly I get it locally from any of the 'Chain' parts stores - for a CS with the correct mounts, just ask for something like a 1986~90 Buick La Sabre or Olds Cutlass Ciera with the 3.0/3.3 Liter V-6 engine and you will get a 120Amp unit with a 12 O-clock mount ...