They differ by the width of wheels (modelwise) & (front) track (year-of-manufacturewise).
The 4/4 (Sports) currently is the most narrow one with it´s 165/80-15 tyres, followed by the Plus 4 with it´s 195/60-15 (or 205/60-15 when alloy-wheeld,205/65-15 as "Sports") and topped off by the Roadster with it´s 205/60-15 (on Alloys), respectively 205/55-16 (on wires)and 205/65-15 (as "Sports").
Easy to be identified by the gap between cowl & headlamp nacelle and/or the top of rear fenders.
2015 Roadster 3.7
