I ran into a intubation tonight where my system jammer was going up against E'tan and I want some clarity about who gets to do what first. Does E'tan get to trigger on the first hit before the jammer can work or does the jammer get to turn it to focus first?

Core Rule Book, Pages 10 and 11.

You're the defender, you get to modify the opponent's attack dice first using your Sensor Jammer.

Yeah that's what I said and the other guys pulled up something that said the opposite so I thought I'd check to make sure.

A case where it's important to remember that the Defender modified dice first. The target's Sensor Jammer can turn a [hit] into an [eye] which may not leave a [hit] for Etahn to turn into a [crit]. Of course if he has a Focus token he could use that to turn the [eye] back into a [hit] and then his ability can turn that [hit] into a [crit].

I'm sure your opponent didn't like that but you could just remind him that if he happened to roll the [crit] in the first place a Sensor Jammer can't do a thing to it. When it comes to the Sensor Jammer you could simply remind him that having, and using, a Focus (or having Marksmanship activated) when he attacks can pretty much negate that upgrade.

Never hurts to carry the rulebook with you.

Yeah that's what I said and the other guys pulled up something that said the opposite so I thought I'd check to make sure.

It would be interesting to know what source they "pulled up", because whatever it was, it was absolutely wrong.

It's always interesting where people get those ideas from.

A case where it's important to remember that the Defender modified dice first. The target's Sensor Jammer can turn a [hit] into an [eye] which may not leave a [hit] for Etahn to turn into a [crit]. Of course if he has a Focus token he could use that to turn the [eye] back into a [hit] and then his ability can turn that [hit] into a [crit].

Do the limitations on modifying dice only once per attack only apply to "re-rolling"? e.g. If you use Elusiveness to make someone re-roll a dice, they can't re-roll it again with Target Lock. Can dice be modified several times otherwise?

To expand: Would this be correct?

1. Etahn shoots at a ship of mine that is equipped with both Elusiveness, and a Sensor Jammer. He scores say 2 hits and a blank.
2. I use Elusiveness to make him re-roll one of the hits, and it becomes an "eye".
3. I use Sensor Jammer to turn the other hit into an "eye"
4. He uses focus to turn both back into hits
5. He uses his pilot skill to turn a hit into a crit
6. I cry about it

Yes, that would indeed be correct. Right down to the crying.

A case where it's important to remember that the Defender modified dice first. The target's Sensor Jammer can turn a [hit] into an [eye] which may not leave a [hit] for Etahn to turn into a [crit]. Of course if he has a Focus token he could use that to turn the [eye] back into a [hit] and then his ability can turn that [hit] into a [crit].

Do the limitations on modifying dice only once per attack only apply to "re-rolling"? e.g. If you use Elusiveness to make someone re-roll a dice, they can't re-roll it again with Target Lock. Can dice be modified several times otherwise?

You can only re-roll any die once, but you can modify multiple times. If you force the opponent to re-roll a die and he has a target lock, he can use that target lock on all except the the one you forced first. A lot of people think modifying has the same restrictions as re-rolling - it doesn't.