The tensioner is a standard wear item, and needs to be replaced every once and awhile, but it really depends on your driving style. If there is a low-pitched rattling noise coming from the engine at idle, it needs to be replaced. The timing chain doesn't wear much unless a bad or worn tensioner has been used for some time. The water pumps on these cars are really quite reliable, it is the ones on later e36-body cars and on that are notorious for failures. My pump has 200k on it and looks and runs like new.
Otherwise, the only other major things to look for in this area are the cam and crank sprockets and loose bolts in the oil pan. The cam gears can be checked by removing the cam cover. The gears should have a flat spot on the tops of the teeth. If these are worn, chances are good that the crank gear is worn too. Be very careful when re-torqueing the bolts on the cam cover-aluminum heads are very easy to strip out.