Need to settle an on going crap-talking debate between some mates and I,

I was convinced for a while that my friend's 1990 G-Limited is running the 117kw/157bhp Gen 2 3SGE (as indicated by the 3SGE wikipedia page) however the car doesn't have a catalytic converter, pointing towards the 121kw/163bhp quoted on the MR2 Wikipedia page. Which one is correct, because obviously the two pages conflict with one another? So far we agree it's the 121kw engine

Also for the Bathurst Gen 3 3SGE, does it produce 125kw or 129kw? There's a lot of mixed info in multiple threads on MR2 Australia

The original brochure from Toyota Australia says the Bathurst produces 125kw, so that should settle that part of the debate at least!
 

 
As for the other question:
 
In the March 1990 edition of Wheels Magazine, the Gen 1 was listed as having 117kw. Modern Motor from June 1991 has the same figure.
 
And just for the record, the BEAMS Red Top has 147kw  
 

So a 8kw/11hp difference between the two then? Thanks for clarifying mister2
If anyone else wants to pitch in/correct the figures feel free

Japanese Wikipedia page says:
 
Gen 2 3S-GE - (rev 1 and rev2 SW20)

• 10.1:1 compression ratio
• 165 PS / 6,800 rpm
• 19.5 kgm / 4,800 rpm

 
Gen 3 3S-GE - (rev 3 and rev 4 SW20)

• 10.3:1 compression ratio
• 180 PS / 7,000 rpm
• 19.5 kgm / 4,800 rpm

 
Redtop BEAMS 3S-GE - JDM Rev 5 SW20

• 11:1 compression ratio
• 200 PS / 7,000 rpm
• 21.0 kgm / 6,000 rpm

 
Note that Australian and European delivered rev 4s are quoted at 125 kW / 170 PS which is apparently due to the addition of emissions equipment, down from the original 130 kW. The gen3 engine is more peaky compared to the gen2 so it will bog down if you don't keep it on the boil.

Hm, so essentially we're back to where we started then

Only issue with that, is it's saying that the Gen 3 makes 134kw then. Which is obviously wrong, the highest debated number is 129kw

The 180PS / 132kW figure is definitely correct for the JDM spec vehicle. You could say that the gen 3 produces anywhere from 125kW to 132kW depending on the market and the year. In practice, the difference is so minimal that you probably wouldn't notice a difference. The torque curve is much more important to performance than the peak power figure.