Dean,
Sorry for the delay, I get no notifications for this forum or topics I've replied to. Kind of annoying.
You can do this all through the OBD2 port, no special cables or tools required. But the first thing I'm going to suggest you buy is a special cable and tool that is required. LOL
1)Need to be able to connect your computer to your vehicle, both the software and I recommend the following cable ($50):
https://www.amazon.com/ScanTool-OBDLink-USB-Professional-Diagnostics/dp/B005ZWM0R4/ref=sr_1_5?crid=JLNJOWVY20ZB&keywords=obdlink+sx&qid=1658260284&sprefix=obdlink%2Caps%2C174&sr=8-5
It comes with software and drivers. It is a pretty nice OBD2 tool that works for any car, so $50 well spent IMO.
2) Need to get some free Saab software called CAN-flasher (T8 Suite is also awesome as its complete tuning software, but you don't need it for standard PCM cloning).
https://txsuite.org/download/t8-suite/
https://txsuite.org/guides/trionic-can-flasher/
3) See if you need to clone/replace your PCM based on the codes/forum, mine threw about ~6 codes with smoking gun being P0245+P0201/2/3/4+P0301. These are all failing drivers inside PCM. I recommend reading the following link to help you assess if you are on the right track and step by step guide on how to clone your old PCM to a new PCM. There are only 2 types of PCM's I believe, so you should be able to easily discern which type you have, and do a like for like Part Number swap (its what I did and had literally zero issues, worked perfectly).
https://www.trionictuning.com/forum/viewtopic.php?t=8094&sid=390e1ee329bf85634facabf64a9adfef
4) Following above guide with PCM cloning is basically connect to vehicle, download .bin files from old pcm, physically install 'new-used' pcm, upload .bin files to new pcm - and done!
I think I can now do it all in about ~10 minutes, so its very little actual work, but please read carefully and follow the above forum link word for word. There is possibility of messing it up if you either check, or uncheck certain boxes. Conversely, it is very clear and apparent which boxes to check/not check, so just do not get in a hurry, and you'll be fine.
Let me know if you have any more questions and I'll help where I can.
- Ian