Ive worked it out, its the 2.5 18valve (3valve per cyl) twin turbo carb fed one.

One of less than 100 RHD coupes made in the 80s too it seems, even throughout their production the RHD coupes make RS500s look common.

185bhp standard (mega restrictive exhaust, low boost, and no intercoolers) but mega short stroke so rev like fook, and 7.8:1 so can be boosted to fuck.

Shite compared to later beasty ones, but still not shy, and it says Maserati on it

Finding it hard to resist