Hi. I presume that you're asking me about my 2.
It's coming close to a 177000 km. It's a '91 SW20 N/A, nothing to be excited about. Just sent it for its first service since I got it a month ago and only getting it back on saturday. Had similar seemingly misfiring running problem like yours, but not sure about the source until i get it back from the mechanic. Felt a sway in the rear occasionally during cornering and I'm not sure if the rear sway bar is screwed or that's how the design of the car is due to the car's tendency to have "snap oversteer". But again, I'll only know when the service is done.
As for mods, the previous owner changed the rims to 17x9 ones ( i think, but 17" for sure), changed the thermostat kick in for the radiator from 180 to 140 degrees so that the side vent fans will kick in once the temp gauge reads 140 degrees.
To be honest with you, the car used to be a written off one and the previous owner got it back registered and VicRoads approved about 2 years ago. He claimed that it was only damage to the rear suspension rod near the left rear end and it happened in the hands of the owner before him, but i suspected more than that. But couldn't find out more or do anything since it ran very well, at least in this month i had it. But it's currently registered till july.
I'm located in the SE suburbs of Melbourne, so probably it's gonna be quite a problem for either of us to see both cars. So maybe we can work out something if you're really interested in it.
Looking forward.
Danny