250.00 is a pretty good price on the belt. On the tensioner though it depends upon what year model S70 you have. If it is the old school hydro tensioner you are looking at over $400.00 in parts alone, that is for a belt, tensioner, tensioner pulley, and idler pulley. This is factory list and I would use nothing less than factory parts. The later model mechanical tensioner is considerably cheaper, only about $225.00 for the parts. Labor is all about the same, I would charge 3 hours for that job so in my shop you would be looking at an additional $210.00 ontop of your parts prices. The serpentine belt and tensioner lists out for another 160.00 in parts and I would charge a nominal fee to change out the tensioners while in there doing the timing belt stuff. The spring seats go for about $35.00 apiece and I charge an hour labor per side and I recommend that you do an alignment when you are done. I charge $105.00 for a complete 4-wheel alignment. So there you have it $650.00 for a hydro tensioner style, $435.00 or so for the manual tensioner, another $180.00 for the serpentine, 210.00 for the seats and another $105.00 for align. All prices are plus tax and plan on leaving the car all day and possibly part of the next. That should give you an idea of what to expect.

Mark