Alternator replaced the day I got it.
Ignition timing was retarded significantly.
Idle speed was wound up to cater for ignition timing.
Electrical faults (secondary cooling fan, power mirrors, glove-box torch)
Gear linkages very loose, hard to find gears sometimes.
Body is immaculate, no rust whatsoever, two dings on the whole thing, going to get them removed very soon.
They're a pig of a thing to work on, due to the early fuel injection system crowding the engine bay somewhat, but once you have a rough idea of what everything is, it starts to come together a bit more.
Parts are a bit of an issue to find, and when you do find them, you pay through the nose. Replacing parts with non-BMW endorsed parts usually a task, for instance, the alternator, I replaced it with the alternator out of my wrecked Mazda E1800 van, a Mitsubishi Electric piece, took a good deal of custom fabricating to fit it and a fair bit of electrical knowledge to wire it in.
Insanely fast for a 1981 car, supposedly pulls about 130 kw/184 hp, from experience, I would say this is pretty well correct, it's an even match for my friends Nissan Skyline R31 (3.0 litre, single overhead cam, fuel injected inline six).
Holds onto the road like it's on rails, McPherson front struts if I'm correct, and also an independant rear suspension/differential setup.
Again, very fast, very powerful. I planted it coming through a roundabout and it the wheels broke free, so I snapped into second gear and they still couldn't gain traction for another 3 metres.
Terrific fun to drive if you're young and male!
Likewise, fitting BMW parts to a Mazda would also be tricky.
I've never tried the Aussie 3.0 skyline (not called skyline, named Pintara GTS1 or GTS2). They also had a South Africa one called the 3.0 SGLi.
You might give the 2.0 non turbo skyline an even match, not the 2.0 turbo, 2.5 or 2.5 turbo - not to mention the 2.5 twin turbo GTR.
I also find it hard to believe you would match the 3.0 unless something was very wrong with it or the driver.
That is looking at factory spec, though most are tuned up cheaply (which is why they are so sought after) such that even the 2.0 would leave you for dead.
BMWs are built better than early skylines, but skylines out perform most BMW equivalents.