Yeah, its just the wines out of the gearbox, its just the way they sound. All BMW's have it, you just hear it more in the E30's because there is less sound insulation. Mine makes the same sound, and it also sets it apart from others, it sounds cool, lol
As for the clicking it is the rockers hitting the top of your valves, because it is an overhead cam, and there are no lifters, there has to be clearences, and when it starts clicking you are able to adjust it, all u need are some feeler gaudges and a paper clip and a 10mm wrench. You adjust the little eccentric cams on the rockers. If you dont know what you doing tough dont try it, bucause u can get floating valves, and you can burn them too. It shows how to do it in the bently repair manual.