Tried a 935 ecu from a '94 940 n/a. It works fine with the '89 245 5-speed, but has better low end torque and is limited in upper end rpm power using the VX cam compared to a 561. Very smooth and better drivability than a good 561. My prevoius results with this ecu were when other components were at fault. Now with everything else fixed or replaced, AMM, speed sensor, coolant temp sensor, speedo sender, it really works great. Other benefits are a better constant idle signal to keep rpm's up while starting with a/c or when the alternator is under load, which is something the 561 had struggled to do sometimes, even when new/rebuilt.
I have used both pink and white 561, pink just quit running, white ran very lean and had intermittent starting problems. The fix with the relay sounds great, but there seems to be a lot of Bosch ecu's out there that will work, so I will quit while I'm ahead.
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon

Well, that's very interesting. I'm surprised to learn that a 940 ECU will work at all. I guess I expected at least some differences in pin out and wire harness changes. So, you feel that the 935 actually results in a better running car? Can you go into more detail about the loss of upper rpm power? Would you anticipate this without the VX as well?

Yes, the 935 bolts right in, and it certainly runs smoother at low rpm's, really shifts great at 1500 rpm with very little pedal. Looses a bit above 4k rpm's but is noticably quieter on the highway. I used to be able to stomp on it and get a significant power surge for passing while in 5th gear and no downshift at 80 mph and 3k rpm's with the 561, and it would roar and jump to 90+ in a heartbeat. Now, it just goes like a regular Volvo, but cruises really well. It was very smooth at 110 mph and it pulls smoothly all the way up to redline in 2nd, just not as jumpy as the 561 was between 3-4k rpm.
Another interesting thing that it has on start-up is the large rpm rise to ~ 1500 rpm like all newer Volvo's have and the 561 didn't have. I think the reasoning behind this is to biuld up oil pressure quickly to provide better start-up lubtication from what I'm told.

The 935 ECU would work really well with the stock cam or another one like a K cam built for turbo performance and high torque, low rpm. It may have the fuel maps suited better for an automatic trans, also. It also would probably do better with an adjustable cam gear to advance the cam timing more than the 3 degrees that the VX already has. Got to get one of those and try it.
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon