Thanks very much for the warm welcome. Stunning cars these 4200's, just brilliant, you get so much bang for your buck...So much car for so little when you look at their Italian cousins. They are such an accomplished car with a racing history that really is quite amazing, to me they are 95% of the performance for a fraction with just as much character. A real wolf in sheep's clothing! The more I and drive it and learn about it, the more I realise it's greater than the sum of it's parts....
From what I have researched so far and from what I understand, the 4200 Coupe and the Spyder M138's had some detail differences/revisions as the face-lift 89 final edition cars prior to the Gransport. The front bumper was slightly modified receiving slightly different intakes/chin spoiler. The front grill was enlarged with a slightly bigger trident badge, they also received venting/meshing at the lower elements of the rear bumper, some of those very late final cars also received the 19" Gransport rims but not all 89 facelifts got those.
The Trident badge in the rear flanks/butresses...This is where things are a little confusing/fuzzy. From what I understand these were standard on the face lift cars. Some say they were an option? Can anyone shed any light? I've seen facelift CC's and manuals without those....
The interior received an update too, the dash instrumentation was revised with different numerical scripting.
The centre console just behind the cambio-corsa panel or stick shift gear lever format, there the face-lifts received a smaller ashtray (losing the Maserati scripted badge) and gaining a cup holder. Nav-Teq remained the same through-out.
Cars through-out production could be ordered with a space saver wheel and the associated toolkit, jack and wheel studs. I've seen cars with this and the boot cover has a slight hump to accommodate this space saver wheel. Mostly though cars came with a Maserati supplied fix a flat type air pump (plug in to the cigar lighter socket type) and Latex cartridge with a flush/flat boot cover. It may also be that (although I'm not 100% sure) in some Markets it was obligatory to have a space saver wheel to satisfy local/country legislation hence some cars came with one as standard.
During it's production life 2002-2005/6 the options Maserati listed were cubby spaces under the rear seats, set of 5 piece fitted luggage, a set of Golf clubs, "Auditorium 200"watt sound system.
Maserati also marketed some sort of special "Personalisation" program, whereby a customer could bring a body colour sample of their choosing and specify it for their car and then combine it with other interior combinations.
Hope this is of use.