Ah yeah, I figured you were running stealth. In general speed/stealth involves more min-maxing and toggling--it's essentially an integrated part of the style and you'll need to do it even for your propulsion at times anyway. With regard to Particle Chargers, at least you're generally not doing as much fighting with a build like that!
I will give a shout-out here for the probably underappreciated Structural Scanner: knowing instantly where hidden doors are can be very helpful in the later levels.
Heh, another believer! There have been a few good players who swear by it, that being the main reason (although it comes with other nice perks, too), but a lot of players don't seem to think much of it, or at least prefer other utilities. I guess I'm one of them--the few times I've stuck with it I've loved it, but in general I don't bother attaching it over other utils.
Maybe it's because with a faster build you can take advantage of existing doors rather than making your own (which could slow you down), whereas with a slower combat build I'm happy to just whip out my melee weapon and make my own door, and the biggest advantage to structural scanners is then just knowing whether enemies can flank you or not. I'll definitely have to play with them again some time.