It makes a fine daily driver IF... you find one well kept.
A well maintained model is hardly less reliable than they were when new. These cars were well designed, but designed to wear out parts. Find someone with full records and you will see how much they ate parts from the get go. On the other hand, find a badly maintained one and you are in for hell, same as any other car.
For those complaining of a loud cabin, try a few newer cars, my Subaru is WAY louder, so is a family members newer Ford Escape. yes, SUV's but still, loud. The New Ford Focus I rented was loud too.
New cars all have problems.
Many Subarus have headgasket issues, Toyotas were gelling engines and now the runaways. My old Honda was the worst car I ever owned for reliability. The Ford Escape I mentioned, has now gone in for paint TWICE due to peeling and the rear window washer if you use it, waters down the inside of the A pillar. The shiny new Focus I rented, worst shifting auto I have ever driven. I don't think I ever found a gear it liked. None are as comfortable as my IS was. In fact the Subaru is going up for sale any day now and I'm more than likely getting another BMW, I just haven't decided which, I have a few options (95' 540I 6speed anyone?).
If you are concerned, buy a cheap second car.
If you can't afford a second cheap car, maybe you should reconsider an e30 anyhow.
For the record, in the 2+years I had an e30,on a badly maintained one...
It had 129k when I got it and I put on over 40k miles.
What it had wrong when I bought it:
Fan resistor (common, cheap and quick)
Leaking steering rack (common, and sped up by using power steering fluid)
Bad gas tank (common, especially in a car from Michigan, a real bitch to change)
Air Conditioner was low on freon (cheap to fix, I used Freeze 12 to refil $40)
Tie Rod End (due to leaking rack, cheap, did a garage alignment)
What went wrong during that 40k?:
Shattered the oil pump (pan bolts)
Blower fan died (got a used one cheap, easy fix) This was a wear issue
2 wheel bearings were going out by the time I sold it. This was a wear issue.
I'm pretty sure that was it, the rest was upgrades or normal wear and tear.
I drove it like I stole it all the time. I never got below 24/25mpg even around town, on highway it could get up near 30.