The roof seals leak. Period. No matter what. I spent about $400 in 1990s money to replace all of them, and it still leaked. And within two years the new seals starting falling apart and it leaked worse. When it lived outside it lived with a shower curtain over it to keep the water out. Of course, that abraded the paint. Fortunately, it is easy to pull the carpets to dry the interior, if ambient humidity is reasonable. Because it will get wet if it rains.
You will smell like burned oil. No, I didn't say you will smell burned oil, but YOU will smell of burned oil. I think it's just the way air-cooled Porsches and VWs are. Like it, live it, celebrate it, but learn to deal with the smell. It will permeate your clothes.
Do not rev past 5600 RPM, period. Ever. No, not even once. The bottom end can't handle higher revs.
They don't have the power to exploit the chassis.
Some people are confused by the heater controls.
There are no cupholders.
In fact, other than the glovebox there aren't many places to stash your stuff. So while you are compensating for your lack of power by pitching it hard into corners your stuff while be flying all over the interior.
They never came with 911 seats, which are my favoritist seats on the planet. Most 914s had vinyl seats, with all the stickiness and sweatiness that implies.
They run hot.
All engine work is done through the little engine lid or from underneath. If you try to adjust the valves, which is done from underneath, while recovering from whiplash you can throw your neck out bad enough that you can't climb into or ride in a car. Any car.
Most of them have a bouncy tach and it's >$100 to fix it. But you have plenty of time to interpolate your revs because, well, see above.
You have to open the front deck lid to fill the gas tank.
It's expensive to upgrade to five-lug hubs so you can run Fuchs. Because, well, you want to run Fuchs, right?
You like body lean, right? Lots of body lean?
Now, if you think I'm hating on 914s, I'm not. I loved mine for many reasons. But you asked to be un-enabled. :-)
David