Payday 2: Complete Stealth in Jewelry Heist Mission

Preparation
Everyone in regular suits
Pistols with silencer

Optional:
Body bags
Security scanner silencer

Rules:
Do not shoot civilians or with a non silenced weapon.
Do not get spotted with masks or killing a guard.
Keep everyone suppressed

The jewelry heist can be completed as long as you do the following things:

• Silently kill guards patrolling the sides of the building (do not do this in front of the window or with others watching).
• Immediately answer their pagers.
• Have two other members wait on the street while this is going on. These two need to keep track of the number of citizens walking around in the street. They will need to be controlled in a few moments. It is best to tie them up.

• After you take out the guards in the back have one member enter the store and tell everyone to get on the ground.
• The other two from the back need to make their way inside to put the people in the back offices on the ground at then assist in the main lobby with crowd control. 
• The one of the guys from the street needs to tell the civilians they scouted earlier to get to the ground then cuff them. If there are more than two then keep then down until there are three in the main lobby then one of those guys need to cuff the remainder civilians walking in the street.
• Once this is complete you begin looting and bagging the items.Have one person going back and forth between lobby and street to keep uncuffed people suppressed and in anticipation of an unexpected NPC appearing in the front.
• The others need to drill (if applicable) and run bags to the van.

Variables:

If you have a higher level with a perk that allows you to answer the pager more effectively then you will have more success at tougher levels.

Intimidate skills will also come into effect.

At higher levels it is possible to do all missions on stealth.

Here is a simple walkthrough of what we did. Apply the same concepts for all difficulty levels.