Loadout that allows for better armor and concealment value of 3
What equipment loadout will allow for the best possible armor while maintaining a concealment rating of 3 for the character?
I do have the ghost perk that improves concealment by 5, which helps with this scenario.
Solution 1:
CAR-4 has the best concealment of 31 out of all primary weapons when fully modified:
- Base Value of 20
- Short Barrel +2
- Competition Foregrip +2
- Straight Grip +2
- Vintage Mag. +2
- Folding Stock +3
Some additional mods can be added without affecting concealment.
Swedish K has the best concealment of 33 out of all secondary weapons when fully modified:
- Base Value of 24
- Grease Barrel +3
- Folded Stock +6
Again, some additional mods can be added without affecting concealment.
Ghost Tier 4 Bonus for unlocking any perk from the 4th tier. +5 concealment.
With this setup, you should be able to wear the Heavy Ballistic Vest, while still being at 3 detection risk. (I'm unable to verify as I'm missing 2 of the required mods for CAR-4, but I'm close enough to be sure.)
Do note that while heavier armour makes you more resistant against bullets, it also slows you down, and speed is important in stealth.
Solution 2:
Since the question asked about the "best possible armor" the following analysis should be relevant: http://www.reddit.com/r/paydaytheheist/comments/2851x6/quick_analysis_of_armor_vs_dodge_mobility_and/
It discusses the trade-offs between dodge and armor value, and (depending on the heist selected) mobility. With Ghost dodge bonuses (which most players will have from taking Fast Hands, and you certainly do with the higher-tier +5 concealment bonus), the best armor may very well be Ballistic Vest with concealmeant 23. That has the further benefit of "freeing up" enough concealment to take one of the optimal weapon loadouts based on damage thresholds (link mentioned in another answer).
Ballistic Vest (23) + Ghost tier bonus (5) + Swedish K max conceal above (33) allows you to select a primary weapon with 28 concealment and still achieve detection risk 3 if you really need it.