Okay, final entries to the Powertrack Plus range. The Tyrone Malone vehicles are exactly as described under the 6V entry.
There are no differences, but a big thank you to a contributor who validated my tale of seeing a Superboss in a Matchbox 75 Blister card pack. He correctly states that a Powertrack version of Malone's Superboss appears in the 1984 Matchbox 75 catalogue with Powertrack wheels and pick ups but with the guide pin removed, (below).
This is great stuff and an excellent example of how this site can be useful. Please keep your observations coming and I thank you all for your contributions!