David brings up an important point here: the 850/70-series rotors are well known to have warping problems when lug bolts are improperly or unevenly torqued. (Cos -- is that why you're having all of these brake jobs done?)

With this in mind, I always re-torque my lug bolts by myself after the car sees the tire man. As for brake and suspension work, I generally do these things by myself, but if I were to have those jobs done by a shop, I'd still re-torque the bolts when I got the car back. I can't tell you how many times I've found that "Joe the Tire Guy" has reinstalled my wheels with 150 lbs of torque on the bolts or nuts. That's asking for trouble on these cars, besides the fact that you'll never get the wheel off if you have to change a flat.

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Jim Rothe, '99 S70 T5M,
http://www.jimrothe.com/volvo/index.html