Primed Thrusters allow you to perform a boost or barrel roll action when stressed. Could a T-70 perform a Tallon Roll, get a stress, boost, trigger PTL, perform a barrel roll (Vectored Thrusters) then end up with two stresses?

This came up the other night with the discussion focussing on the " or " on the Primed Thrusters card. As in you can perform one or the other but not both.

Anything in the rules that prevents you from doing both boost and barrel rolls with PT and PTL?

Yes. Primed Thrusters does not indicate any limit on how often such an action may be taken, only that you can perform either action while you have 1 stress. In your case, both actions are legal as each was performed while you had one stress.

with "Snap" Wexley it's prety deadly as you get the free boost with primed truster after K or Talon