Help with my gear as a gunner

So, right now i'm at 3* and not sure how to progress currently i have
Gunslinger sash
Gunslinger Cap
Antigua
Needle Shot
Planned for 5*
??? sash
??? cap
Argent Peacemaker
Blitz Needle
???
Swiftstrike Buckler
AS you can see, i can't decide on which 5* Gunslinger set to go with and i need a 5* Shadow gun. I don't wanna go with Dark CHaingun cause i already am going with blitz and i like to be mobile, and no sentence because again, i already have A-Peacemaker. I considered the shadow pulsar but that's more of a swordsman sidearm.
Thoughts?

You accidentally made two copies of this thread. Please move this copy to the Graveyard (by editing the original post and selecting that forum from the drop-down menu).
Everybody else please respond here.
Edit: Darnit!

You'll want another elemental weapon. Argent Peacemakers aren't that good as your sole DPS weapon. If you want a damaging elemental gun, you'll want a Nova Driver.
Dark Chaingun is the best Shadow Gun IMO. However, if you're not going to go with that, I'd recommend the Umbra Driver. Tundrus is more of a controlling gun with it's freeze. As a gunner, you need your guns to do... well... damage.
If you want an simple gun that works everywhere, I recommend the Iron Slug and/or Pepperbox.
For armor, I'd highly recommend the Perfect Mask of Seerus. If you can't get operation Crimson Hammer, you'll want at least one piece of the Chaos Set. You'll be relying on Charge Attacks quite a lot, but the status vulnerabilities on Chaos are really painful if you're not used to it. Ideally, you'll want to pair it with another armor piece. If you're keeping your gunslinger set, I'd recommend the Shadowsun set.

Since this thread is winning, I'll copy my post from the other thread:
Have you read the Gunslinger Guide on the wiki? It's not great, but it covers a lot of the basic questions quickly, so that you can ask more specific questions here.
For armor, you might want to give my detailed armor guide a read. It's not quite finished, but the parts on gunner armor and general armor strategy are ready for you. If you want to continue your current armor line, which is fine, then I recommend Shadowsun.
For guns, you already know that you want one of each damage type. You should also sample all of the styles, because that's a lot of the fun in this game. My advice is to get Umbra Driver, because (A) you haven't tried alchemers apparently, (B) you don't want Grim Repeater, (C) Winter Grave's charge is disappointing due to the freeze, (D) Sentenza/Obsidian are antiguas and hence weak, (E) Biohazard is too weird for your first shadow gun.
The endgame is filled with shadow monsters so the Shadowsun set should work nice. I would also check into the numerous armor lines you can get through the Padded set. They can fill nearly any need a gunner has.
For your shadow gun I would suggest either the Shadowtech Alchemer or the Tundrus lines. Both are charge oriented guns that can be very powerful. The Alchemer has a higher skill ceiling and can deal massive damage when aimed right. The Tundrus can Lock targets in freeze and deal heavy damage, the downside here is that you need to aim at the front of the target and the regular shots are fairly weak.