if anything after we got both elemental primeds that's the only build you need for pistols, have fun when it does come out lol

Mods Choice

-The obvious Multishot+Status Galvanizeds, as per ussual you end up getting much more status/crits just from the multishot, that applies to basically every weapon in the game so it should be the same thing here, and since that's the case if we put the status galvanized together just from status effects you can get up to +600% damage just because of them.
-After we got the electricity galvanized the only combo you will ever need is Corrosive+Heat in pistols, being able to combo both primeds is a god send, now add to it that with the status effects from it you get 90% armor reduction(80% from Corrosive then the 50% on what's left from Heat), and all that extra damage is just dumb as hell.
-And from Ruffles in the comments, using Creeping Bullseye in the place of Primed Pistol Gambit you won't get the firerate debuff since [Semi-Pistol Cannonade] locks up the firerate, and 1 less forma in the end, Thank You for the suggestion!

Extras

Well honestly I don't see anything usefull to put for the exilus mod, get what you like/fits with your gameplay style and be happy!

Also if you plan to always hit headshots [Galvanized Crosshairs] would be a pretty good idea to use, I prefer to build for convenience so I chose to not use it.