I'm planning to replace timing belt on my 1992 D90 200TDi by myself. I got factory and Haynes manual, but I would like to know how difficult the job really is. Are the special tools really required or can it be done without them? Are there any other parts except the belt that have to be replaced, like gaskets, seals, tensioners.. etc? The engine has 230000 km on the clock, I have no records of previous maintenance so I'm replacing the belt as a precaution.