I plan to replace the gasket on my B23 this weekend. Any hints?

You know, I thought of that after I replied, and said "Of course he will drain the oil!"
Can't take anything for granted, right?

To further ellaborate on the tightening procedure, which is basically correct, I would go a step farther and hand torque all bolts while the RTV is fresh, wait overnight for it to set-up and finish the bolt torque to the recommended 7-12 ft lbs the next day. Otherwise the sealant will squeeze out completely and place a bead into the pan which can fall off and get in the engine internals. Don't use too much sealant, a thin smear is all you want.
Note that you can easilly torque the bolts by hand to 3-5 ft-lbs, so the torque shouldn't be much!
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon

drain the oil first! Make sure you torque it back on correctly, finger tight first. I use a large piece of cardboard under the car to catch all of the dribbles.
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98 V70Rawd(101Kmi), 95 854T(85K mi), 88 245(165K mi)

Get the three piece gasket and jack up the engine one to two inches after removing the motor mount nuts (but not more than the lenght of the studs on the motor mounts) Place a jack under the front pulley and one under the tranny so the pan can drop down about an inch. Scrape all the old gasket material off cleanly and seal the new one back on with red, hi temp RTV.
This is a PITA job, and is almost better done with the engine out of the car, or at least a hoist to lift the engine up off the mounts to get better access.
Good luck!
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon

That's what I thought. It looked to be a much more difficult job than one might first suspect. I may put this one off as I've got a new water pump and thermostat that I could install instead.

The risk of leaving the pan dangling on the oil pump is that bits of the old gasket and sealant will fall in. You really need to get the pan completely clear, which is possible with the engine in situ but not easy.
When you have replaced the gasket, you need to re-check the bolts after abouit 100 miles. I have found them loosen a lot as the cardboard gasket gradually flattens, and the source of a considerable oil leak.