So, the Core Books (the language is identical in all three) state that:
QuoteVICIOUS (PASSIVE)
When this weapon scores a critical injury or hit, the character adds ten times the Vicious rating to the critical roll. With Vicious 3, for example, the victim adds +30 to his critical hit result.
But also:
QuoteNote, that talents and qualities that specifically affect Critical Injuries do not effect Critical Hits (so the Vicious quality, for example, would have no effect on a ship or vehicle).
My knee-jerk reaction is that these contradictions are just due to a bad example, as Vicious specifically affects both Critical Injuries and Hits, and a better example would have been Lethal Blows (which specifically only affects Critical Injuries), but has there been any official clarification on this? I haven't found anything in the Erratas, FAQ or Dev answer thread, so I'm curious how you guys would rule it before bothering the devs with it.
To further complicate things, there aren't any vehicle weapons in the Core Books with Vicious, but off the top of my head I can think of at least two from later books (the flak cannons from LBE, and the Plasma Drill from FO).
It kind of makes sense that a serrated blade wouldn't do more damage to a speeder bike, but then again, why would a plasma drill only do worse crits against people if vehicle weapons by default already get +50 to Critical Injuries?