Basically, when it comes to Jspec VR-4s there are no less than 11 different variations.
But put simply, there is pre-facelift (1987 until October 1989), and there is facelift (October 1989 onwards). The pre-facelift VR-4s had 205hp while the facelift models had 220hp. Now of the facelift VR-4s, they were available in either Evolution or non Evolution, but I think the Evolution wasn't available until late 1990. The Evolution models had 240hp as they had a larger intercooler, 510cc injectors amongst other things such as a four bolt rear end, hood and extra bumper vents etc. The only way to truly spot an Evolution is the gear ratios. 3.909 = Evolution, 3.545 = non Evolution. Also the inlet manifold saying 'ECI MULTI Turbo Intercooler' as opposed to 'CYCLONE Turbo Intercooler' is another way to spot an Evolution.
The RS is a lightweight model, and in the E38A it was without 4WS. You could get a pre-facelift RS (205hp), facelift RS (220hp) or a Evolution RS (240hp). Please don't confuse all facelift RS models with the Evolution model, although a non-Evolution RS is not common at all.
The commemorate the VR-4s win in Monte Carlo the Monte Carlo model was relased in 1990 (facelift) and was available in either Evolution (for the manual models) or non-Evolution (for the automatic models).
Here's a run down copied from another forum differentiating all VR-4 models
09/87 - 09/89 Jspec Galant VR4 (Manual) E39A-0###### SNPF 205(150.7)@6000 rpm 294Nm @ 3000 rpm MD128618 5spd 3.545 TD05 14B 450cc Y 1340 Kg Original VR4
09/87 - 09/89 Jspec Galant VR4 RS E38A-0###### SNPF 205(150.7)@6000 rpm 294Nm @ 3000 rpm MD128618 5spd 3.545 (LSD) TD05 14B 450cc N 1300 Kg Lightweight RallySport version (Windup windows, no climate control, no 4WS, later ones have RS-E driveline)
10/89 - 07/90 Facelift Jspec Galant VR4 (Auto) E39A-0###### SRPF 210(154.3)@6000 rpm 294Nm @ 3000 rpm MD153695 4spd Auto 3.307 TD04 13G 450cc Y 1370 Kg First auto VR4
10/89 - 07/90 Facelift Jspec Galant VR4 (Manual) E39A-0014000+ SNPF 220(161.7)@6000 rpm 294Nm @ 3500 rpm MD150427 5spd 3.545 TD05 14B 450cc Y 1340 kg Facelift VR4
10/89 - 07/90 Jspec Super Galant VR4 (Manual) E39A-0014000+ SNPF 220(161.7)@6000 rpm 294Nm @ 3500 rpm MD150427 5spd 3.545 TD05 14B 450cc Y 1380 kg Luxury Trim VR4 (Leather etc)
10/89 - 07/90 Jspec Super Galant VR4 (Auto) E39A-0014000+ SRPF 210(154.3)@6000 rpm 294Nm @ 3000 rpm MD153695 4spd Auto 3.307 TD04 13G 450cc Y 1410 kg Luxury Trim VR4 Auto (Leather etc)
10/89 - 07/90 Facelift Jspec Galant VR4 RS E38A-0###### SNPF4 220(161.7)@6000 rpm 294Nm @ 3500 rpm MD150427 5spd 3.545 (LSD) TD05 14B 450cc N 1300 kg Lightweight RallySport version (Windup windows, no climate control, no 4WS, later ones have RS-E driveline)
90 - 93 Aspec Galant VR4 E39A SNPF 201(148)@6000 rpm 279Nm @ 3000 rpm MD165810 5spd 3.545 TD05 14B 450cc Y 1450 kg Special version for Australian Domestic Market, similar to USA Spec
90 - 93 USspec Galant VR4 E39A SNPF 201(148)@6000 rpm 279Nm @ 3000 rpm MD165810 5spd 3.545 TD05 14B 450cc Y 1450 kg Special version for USA Domestic Market, similar to Aust Spec except for leather, LHD and auto seatbelts
08/90 - 03/92 Evolution Jspec Galant VR4 (Manual) E39A-02##### SNPF 240(176)@6000 rpm 304Nm @ 3500 rpm MD165808 5spd 3.909 TD05 16G 510cc Y 1350 kg VR4 Evoloution - GSR
08/90 - 03/92 Evolution Jspec Galant VR4 RS (Manual) E38A-02##### SNPF 240(176)@6000 rpm 304Nm @ 3500 rpm MD165808 5spd 3.909 (LSD) TD05 16G 510cc N 1310 kg VR4 Evolution RS - Also known as the EVO 0 or RS-E
08/90 - 03/92 Jspec Galant VR4 (Auto) E39A-02##### SRPF 210(154.3)@6000 rpm 294Nm @ 3500 rpm MD165809 4spd Auto 3.307 TD04 13G 450cc Y 1380 kg VR4 Auto
08/90 - 03/92 Monte Carlo Galant VR4 (Manual) E39A-02##### SNPF 240(176)@6000 rpm 304Nm @ 3500 rpm MD165808 5spd 3.909 (LSD) TD05 16G 510cc Y 1410 kg Special Luxury Evolution model to celebrate success in the Rally of Monte Carlo
08/90 - 03/92 Monte Carlo Galant VR4 (Autol) E39A-02##### SRPF 210(154.3)@6000 rpm 294Nm @ 3000 rpm MD165809 4spd Auto 3.307 TD04 13G 450cc Y 1430 kg Special Luxury Evolution model to celebrate success in the Rally of Monte Carlo (Auto)
The one above I have highlighted is the model I have, although it's not usually referred to as a GSR, and further down where it says the RS-E model is known as the Evo 0, the Evo 0 term is actually applied to all Evolution VR-4 models, not just the RS models.