It took me five years too. From 2003 to 2008 with a lot of research. I knew how much fun a classic Mini is, with no real power but incredible handling. That's the essence of 4/4 ownership. I knew what is was like behind a V8 Rover engine after 22 years in an MGV8. My logic was to go for a Plus 8, without really understanding how complex that decision would be, and only a long time after, did I realise this. And bought my Roadster anyway, even knowing about low ground clearance of the sump.
There are a couple of simple factors amongst all the detail. These are that the Roadsters have better weight distribution than the Plus 8. Simple physics. The Plus 8 goes on torque, the Roadster on revs. Second factor is that the Plus 4 engine in a 4/4 body gives increased power with agile handling. The Duratec is easier to live with than the GDI. The Duratec is a lot more tunable.
If you value a treated ash frame, a stainless bulkhead and galvanised chassis, then it has to be a long door, 1997 is the odd ball year when you could get any of the changes in one car, from mid year.
After that it depends on personal choice of colour. interior trim, dashboard style, and wheels. If you chose no spare wheel and no opening in the rear panel, then any issues with fuel tank and pump, or leaf springs becomes much more difficult to access. MMC should have used a removable cover on the rear panel but it was easier in build not to.
