My certificate has brought up some confusion when I registered my Plus 4 in Portugal. I only noticed last year, during scrutineering for a hill climb, that my registry papers state my car model is a 4/4. And I had never noticed it before.
When I checked the certificate, I noticed the car model is described there as being "4/4 2000".
I had an email exchange with Mark Ledington about this, and here's what he wrote to me.
Hi Mario, hope you are well.
Thank you for your email.
...
The second issue is easily explained – all cars are variants of the 4/4, so we have the 4/4 1600 (the 4/4), the 4/4 2000 (the +4) and the 4/4 3000 (the Roadster)… the CofC is correct and so I hope this helps to explain to your Portuguese authorities.
I believe that Jorge has the full homologation document, which explains these variants in great depth… (if not, he can get them from Matt Welch)
With best wishes, looking forward to seeing you in the summer
Mark
(note: "first issue" regarded some details about my M3W order)