I think if you get a good car for $150 range you are doing great. The early cars are great cars, but they are getting old.
In its history my 91 had a full repaint and engine rebuild (Cam tensioners weren’t updated under recall and caused cam issue). The interior was redone.. so by all accounts it was a great car. However once I got the car I noticed the steering seemed loose. Needed a steering rack. The front brakes had been upgraded to the bigger brembo’s. However the rear calipers were original. They were in horrible shape and one of them was seizing. They needed love. So i decided to upgrade them and do the big brake kit as well on the rear to match the front. The bushings are known to possibly go bad. I inspected all of mine and they are actually in good shape, but there seem to be a couple the might not be a bad idea to replace. Probably going to do that shortly..
My point is, any of these diablo cars are most likely going to need love in places. A top tier car would be one that has been completely restored and all items are refreshed.. I’m not sure anyone is out there doing Diablo’s like they have been doing countach’s. So a top car that hasn’t been refreshed would be a hard find and you’ll pay up for it. Luckily the 91-92 cars are actually pretty affordable and parts are actually available and affordable. The early diablo’s are fast.. and light... but they are a mans car. It takes quite a lot of effort to drive them. Don’t be afraid of one, but understand it. It’s a good reason why miles are lower on most of the earlier cars.