I think Amir/Stun Gun could really go either way.
If Amir can keep it on the feet and make it a striking match--and if he's smart, that's what he's going to want to do I think--then Amir will probably win it. Stun Gun's striking is functional, but I haven't seen anything yet that's overly impressive. With that said, he does have a whole slew of KOs from earlier in his career, so if he hits Amir just right that could be all she wrote.
If the Stun Gun turns it into a grappling match I suspect it won't be good for Amir. On the ground, Amir ends up on this back too much, and I don't think he'll be able to get the sub. Stun Gun's judo/top control wrestling is too good.