Spellslinger's Arcane Gun question

[John of Arc]

If a spell requires an attack roll and a save, do I get to apply my gun's enhancement bonus to both, or do I need to choose to apply it to one or the other?

[ShadowcatX]

It says "or" so RAW you'd have to choose.

As a DM, I'd definitely change that.

[Merck]

I cant check my books now because i am at work but I was under the impression that the caster "shot" the spell throgh his weapon using the firearms touch attack mechanic on the first range implement of said weapon.

That would make it much more easy to hit your targets even if you are using the enhancement bonus on the spell DC, which you should, all the time.