Sounds like a nice car. Make sure to look under the car for any signs of rust of bubbling in the paint. For some reason the sunroof panel is a hot spot for rust. Check under the car for any leaks, I am going through getting a new steering rack on mine, its not fun or cheap. Oil pans leak also, these arent things to stop you from buying, just to look out for, they can get pricey. Also!!!!!! if the owner doesnt know the last time the timing belt was replaced, replace it! do the belt and water pump at the same time. If all the gauges work and electrical items are sound, the car sounds like a great find.
A 318i can be a fast car, esp with the 5spd. You dont want a perfect car either, you need something to keep you busy. Keep us posted with what you decide, I would DEF. go for it!