914/4's are mainly good because they're VWs that Porsche didn't want to have the VW badge on. To check if the body is straight and hasn't sagged, remove the targa top, open both doors, and then see if the doors close properly. Many of the parts are straight off VWs, making them cheap and easy to obtain. Many bug shops also work on them and likely have one or two out back. Engine access isn't as easy as a beetle however.
One thing that is worth keeping a note of is if smog testing is done where you live. That can change which cars are favorable toy cars and which aren't. Don't overlook old trucks for the learning experience. They're simple, things are easy to work around, and they're generally able to run alright even when they've been shot and left for dead. A friend of mine picked up a '53 GMC truck for $25 at an estate auction, put a new battery in filled it with gas, and drove it home. No, there's no digits missing from that price.