A thorough PPI should be your top priority on either of these cars. Find a BMW specialist and split the cost with the owner (even if he/she doesn't sell the car to you, they will have a PPI in hand for next buyer).
At 130,000 kms, I would find out if the shocks are original. If they are, they should be changed. Anything rubber in the suspension --all bushings and mounts should be in consideration to be changed. Common wear items like the water pump, front control arms and hoses are entering the replacement phase. The car will run and go fine if you don't do any of this, but will not handle in "as new" condition.
Drive the car. Everything should feel very tight and buttoned down. There should be no floaty-ness or bobbing when cornering or going over bumps. Anything that feels amiss is probably worn suspension component(s).
The rear shock mounts (top) also frequently wear out at this mileage. You need to remove the carpet in the trunk to check their condition.
Pay special attention to the rear toe arm. The bushing that locates the arm to the body is well known for wearing out. If it is worn, the mounting/carrier can tear, leading to very expensive welding.
We never got the "Euro" motor here in the US.. all our cars have the gimpy 240 hp bored and stroked 325 motor. So I have no advice there except to say make sure you see receipts for services. I understand the S52B32 needs periodic valve adjustments.
Also, there is a plastic underbody tray that is located just under the front of the car. It extends from front bumper to just fore of the engine. It is common for people to tear/damage this piece going up and down ramps and inclines. The cheap plastic grommets give way and poof it's gone. Not a big deal, but annoying. There are also two additional aero elements on the sides down there. These "porkchops" can also be damaged.
The radiator is weak in our US spec version. I don't know if the "Euro" motor uses the same part, but if it does, this should also warrant a close inspection.
All I can think of off the top of my head. It's been years since I've had an M3, so while I hope everything I've posted is 100% accurate, my memory sometimes fails me. I would look for a more updated/comprehensive/accurate list on the net somewhere. bimmerforums or m3post would probably have a good one. Unofficial E36 is also a very good site.
BTW, I like the Estorilblau one with the forged/polished wheels (the 97). That thing is the hottness. Loose the eyebrows, though. Makes the car look narcoleptic. The wheels were an (expensive) option here in the US and are much lighter and stronger than the stock cast wheels.
The Alpineweiss car looks like the trunk lid doesn't align properly on the left side. Could just be the angle, though. But if body parts don't align perfectly, that usually indicates an accident and a ghetto repair job.
M
(I can compare the looks and sounds, Holden wins IMO 
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