This question has been heavily debated in this 8 page thread from 2007. However if I remember correctly, that was LRB5, back when stunty was still +1 to the injury roll. That thread specifically mentions modifiers to the injury roll. Stunty no longer modifies the injury roll, so I'm wondering how it works with stab now.
For reference, here are the texts of the two skills. Emphasis mine.
GW Competition Rules wrote: Stab (Extraordinary)
A player with this skill is armed with something very good at stabbing, slashing or hacking up an opponent, like sharp fangs or a trusty dagger. This player may attack an opponent with his stabbing attack instead of throwing a block. Make an unmodified Armour roll (except for stakes) for the victim. If the score is less than or equal to the victim's Armour value then the attack has no effect. If the score beats the victim's Armour value then he has been wounded and an Injury roll must be made. This injury roll ignore all modifiers from any source - including Niggling injuries. If stab is used as part of a Blitz Action, the player cannot continue moving after using it. Casualties caused by a stabbing attack do not count for Star Player points.
GW Competition Rules wrote: Stunty (Extraordinary)
The player is so small that they are very difficult to tackle because they can duck underneath opposing players' outstretched arms and run between their legs. On the other hand, Stunty players are just a bit too small to throw the ball very well, and are easily injured. To represent these things a player with the Stunty skill may ignore any enemy tackle zones on the square he is moving to when he makes a Dodge roll (i.e. they always end up with a +1 Dodge roll modifier), but must subtract 1 from the roll when he passes. In addition, this player treats a roll of 7 and 9 on the injury table after any modifiers have been applied as a KO'd and Badly Hurt result respectively, rather than the normal results. Stunties that are armed with a Secret Weapon are not allowed to ignore enemy tackle zones, but still suffer the other penalties.
So stab says no modifiers. Thats fine.
Stunty says that after all modifiers (of which there can't be any), you treat a 7 as KO, and 9 as Badly Hurt.
So by my reading, you can't have any modifiers to the roll, then after applying that, if you've got a 9, it's a badly hurt?
The reason I'm asking for opinions on this is that it came up at a tournament recently, and the only clarifications I can find on here is from back when stunty was a +1 to the injury roll, which is quite different to how it reads now.
So, opinions. Stunty affects stab rolls? Or not?