Do you want to turbocharge the B230F, or are you looking to turn the car into a naturally aspirated 940?

The B230F should drop right into the '93. If memory serves, both cars run LH 2.4. Of course, this gives you a naturally aspirated 940.

You can tap the block and add the oil lines that the turbo would need, then just slap on the exhaust manifold from the '93 complete with turbo. If you run stock boost you shouldn't have any problems.

On the other hand, the bottom end of the '93 is stouter. You could slap a new head gasket on there, have the head rebuilt while its out, and drive the car another 200k. This would also give easy access to the Pcv plumbing and the front seals. Probably less work than swapping engines.