The torque spec for knock sensors is 14-18 ft-lbs. Although a debatable issue, to minimize sensitivity it has been recommended to use a minimal 8-12 ft-lbs with a drop of thread locker to hold it. A couple of master techs had that debate here on the brickboard back in 1997 as I recall. You may not notice much difference, but I swear I noticed a slight improvement on my B234F although some of that may be in the category of cars running better after being washed. I've done it with all my Volvo's since then. If you tend to use lower than the recommended octane gas (and your 94 turbo likes at least 91 octane) or if the car is used a lot in the city where it will tend to accumulate more engine deposits at lower revs then I would use the minimal torque to try retaining a tiny bit of the pep you lose when the engine knocks and the timing gets retarded. It certainly won't hurt.
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Dave -not to be confused with a real expert, just goofing around at this