I support BMTech..
I got my ride a 1997 model so engine is M43 (newer) Most 1992/93 318 comes with M40 engine. 318 is a 4 potters so some maintainance are cheaper, oil change is one.
My advice is to spend a little more and get a post 1997 328.. The roadtax can be higher but the technology and engine are much superior. Many go for 325 as the power is almost the same as 328 but 325 are only available in 94/95 therefore technology is less advance then 328 post 97 but cheaper..
Read Anxious thread, he just got his ride recently a 325.
My search for E36 is since Nov 96 and only in April I found my ride. Many adviced me to get a 325 but not many well maintained 325 out there, more 328 in better condition as most are company car therefore repair are paid by company.
1992/93 E36 are cheap but do request for service record, if BMW is not sayang by the owner, it will give you a lot of problems and will demand a lot of $$$ from you.
Important is ask for good service record and have your car check by few workshops.
My personal advice is ... When you bring the car to the workshop, said it is your car and need them to check for what to repair. They will give you more details then when you said you are buying the car.