150k km (100k miles) on a E36 should be okay. My M3 just topped 110k miles. I've seen a few E36s over 200k miles (320k km), so thats a testament to their longevity. Again, like all German cars, it is about maintenance. And preventive maintenance at that, replace things before they break.
Like I said earlier, the biggest thing about the any BMW is its cooling system. Other weak points for the E36 would be the rear shock mounts, and rear frame support. If you do not beat the crap out of your car, the rear frame should be okay, but check it anyways. The Rear shock mounts definitely need to be upgraded. And other suspension bits and brushings should be checked out. There are certain production years that have issues with the VANOS, I do not remember.
Other than those few points, the E36 should hold up well. Of course the other issue like I mentioned earlier is the interior. I feel that BMW went cheap a bit in the E36 interior, so given its age and wear, I think a E30 of the same vintage would hold up better than the E36. Nevertheless just keep looking I am sure you will find one that is in good condition.
Another note of caution, do not buy Dove Grey Interior, unless you really really really LOVE it. It looks great when new, but it is really hard to take care of. I learned that on my E36 328is (Arctic Silver on Dove Grey). In the M3, I got Alpine White on Black.
Here are some links that are useful:
http://www.edgemotorworks.com/sindex.htm (click on the E36 section).
http://tinyurl.com/uvp4q
http://www.bimmerzone.com/inspection.htm