the big problem with the Saab shifter is the POS reverse lockout ring. This ring hooks into the Saab knob.
To remove the knob there is the recommended method of taking a hacksaw to your old knob and cutting it in half to release the reverse lockout ring.
The other way that takes more time is to use picks to release the tabs on the lockout ring that click into the knob, then unscrewing the knob.
You will need to decide whether you want to keep the lockout ring or take it out. Be aware that the leather shift gaiter attaches to the lockout ring and you will need a way to attach the gaiter to the new knob otherwise it will look like your grandma's pantyhose.
The mods I've done to my own car have focussed on speed, handling and stereo. So this reflects my priorities.
Stick the saab knobs. They don't look as trick but keeping the reverse lockout ring with an aftermarket knob that doesn't mate to it, looks pretty rough. Similarly, removing the lockout ring mechanism will make your gaiter look saggy.