Suzuki Cultus NomenclatureThe family of cars derived from the original Suzuki Cultus have been manufactured in seven countries, in four body styles  under nearly a dozen nameplates worldwide, chiefly Geo Metro, Chevrolet Metro, Suzuki Swift, Suzuki Forsa, Suzuki Cultus, Pontiac Firefly, Chevrolet Sprint, Subaru Justy as well as nameplates in Japan, Pakistan, China and India.
There are two primary ways to organize the vehicles: 
 Mark (Mk)  or 
Generation. Each method is appropriate in a certain context, just 
 be aware which system you are using. 
The Mk System:Mark or Mk : vehicles distinguished by global region --  marking cosmetic restyling changes or mechanical changes but ignoring other global regions or current production in other regions.  Outlined here are Mk systems for North America, Europe and Australia:
NA Mk: (North American Mk)  Teamswift is structured around the NA Mk system:
Mk1 85-88 (Boxy body + Boxy dash) (through 2004: South America)
MK2 89-91 (Round body + Boxy dash)
MK3 92-94 (Round body + Round dash)
Mk4 95-97 (Guppy mouth)
Mk5 98-01 (Razor mouth) 
 EuroMk:
EuroMk:MK1 - 86 to 88  (Through 2004: South America)
MK2 - 88 to 92
MK3 - 92 to 96 (styling refresh)
MK4 - 96 to 01 (styling refresh)
MK5 - 01 to 02 (styling refresh)
MK6 - 05 onward
The EuroMk's:
 Australian Mk:
Australian Mk:  MK1 - SA310 / SA413 (1984-86)  (through 2004: South America)
MK2 - SF310 / SF413 / SF416 (1989-92)  
MK3 - SF310 / SF413 / SF416 (1993-99)
MK1 Introduced March 1984, the SA Swift was front wheel drive, with a solid axle and drum brakes on the rear, with front disc brakes. Models: GA, GL, GC and GLS.
MK2  New rounder body shape with mechanicals similar to the SA model and the solid rear axle replaced by a trailing arm setup. Models: GA, GL, GTi 3-door hatchbacks; GL and GLX Sedans, with 4WD available between 1990-91.
MK3 Remodeled interior, revised front and rear bumper fascias. New rounded dashboard. Models: GA, (later replaced with the City Car), the Cino, GL and GLX Sedans, and the GTi
The Generation System:  This is a single global system that distinguishes the cars by major exterior styling change + major engineering change... and may overlook intermediate styling facelifts and local idiosyncracies.   The 
Wikipedia Suzuki Cultus article uses this system:
 Generation I
Generation I 1983-1988 (through 2004: South America)
Cultus based, 3/5 door on 88.4 in & 92.3 in wheelbases
First marketed in the JDM as the SA310, followed by
Cultus, Forsa, Sprint, Swift and Firefly nameplates.
Generation II  1989–present
Cultus based, Co-designed with GM
3/4/5 door + convertible on 89.2 in and 93.1 in wheelbases 
Still in production today in Pakistan and China (5door), 
includes Cultus (JDM), Swift, Metro, Firefly, Subaru Justy, Cultus (Pakistan), 
Chevrolet Sprint (Colombia), Holden Barina, Suzuki Lingyang (China) nameplates.
Generation III 1995-2001
Cultus-based, North America only, Co-designed with GM
3 door and 4 door sedan only, 95-2001 only, 93.1 in wheelbase only
Structurally re-engineered not just re-styled, twin airbags,
Geo Metro, Chevrolet Metro, Pontiac Firefly, Suzuki Swift nameplates.
Generation IV 2004-present
Non-Cultus based, Europe/Oceana/Asia only (so far)
The Suzuki Swift, one nameplate worldwide.