At the moment there is little reason to craft a taser with a higher quality electroshock generator since a quality 10 has an equal chance to stun as a quality 160 one.
Idea for solution, maybe taser should ignore a percent of fortitude based on quality? Up to ignoring 40% fortitude as 160 quality.
Alternatively you could increase the attack rating of the taser stun based on its quality (not damage, am talking about the skill that is checked against the enemies fortitude)