Preliminary codicils:
1. This is written from the perspective of a trad Plus 8er with lots of Morgan experience.
Plus 8s are better suited to North American LONG highways and their technology straddles two automobile cultures rather than one, so I started with and stayed with that model, though I have experience of all models and eras. . 2. Few can understand car specs any more.

At most, they look at the bhp and then list the add-ons now used to replace driver skill.
Too often, pre-2004 4/4s get a cursory dismissal because of misunderstanding their performance side on paper. But bhp alone is unimportant, while power-to-weight is everything. For whatever reason, pre-2004 4/4 were always placed on a much lighter chassis than the Plus 4s, Plus 8s, Roadsters and all that came after.
The later cars largely handle the same, albeit a little more heavily as time goes on. The noted 4/4s conveyed a more exciting ride and handling than their untouched contemporaries, and are very susceptible to power upgrades which are more potent because of their much lower weight. However, changes are not often done because of model designation stays the same. Dumb but true.
You might be interested to know that the development director of the day, Bill Beck, who designed the first Morgan V6 using the US Continental variant on a 4/4 chassis, shunned what he thought was the unnecessarily heavy Plus 8
chassis which nonetheless was adopted for all Morgans from 2004. That car, even with only 204 bhp, was a virtual bomb compared to the later outsourced design.
Ergo, by extrapolation, the trad Plus 4s are merely cheaper Plus 8s, same weight, lower bhp. They became a parts sourcing problem some time ago in their iteration after 1987 to 2000.
I know where and what to source because of their close fuelling relationship with Plus 8s, but most owners/dealers get frustrated.The trad Plus 8s are infinitely (the most of all Morgan models) upgradeable and robustly served by three supply markets (if one includes Australia). BTW, I ignore petrol prices as I have no wish to limit my hobby with this factor. After all, if I was looking to save money, I certainly wouldn't get into Morgans!

The only move I have made about fueling (outside of its management)which is to make sure (a Mulberry Goldman designed fuel tank in ss) I have a range of more than 300 miles. There is a massive buffet of personalization possible. However, the fuel cost thing has lowered their residual prices.. We are all trained by current advertising..even in respect to our hobbies. Actually, you can save a decade or two of the extra cost of their petrol now in buying one instead of a Roadster.
The other advantage of a trad Plus 8 is in its acceleration over the Roadster. Trad Plus 8 are better geared and engined for the legal speed range we all must follow. Most of what they have is packed into 20-100mph.
The first two Roadster variants, with Mondeo and the Escape engines are excellent Morgans, with only a bit of sorting needed. However, they allow far less owner engine interaction and upgrades.t They are more suited to the newer Morgan demographic.
If you are not into upgrading your current car, (understandable) I would try one of each of the others. Remember, pre-1999 cars easier to electrically sort and source and pre-1996ish cars have a surer change of getting for the right wings (ex-Factory from their original supplier who is supplying again) , though even amateurs can repair steel wings and the original alloy wings rot at the edge in ways that cannot be properly repaired.
L.