Its not a BOV issue, it is a fuel enrichment issue.
You are experiencing fuel bog with the AFRs you are showing.
I'll get with Mefiburn Bob and get some updates worked out with new fuel enrichment at lower RPMs.
I'll get with him next week. Call him late next week.
You have a Tial blow off valve and that most likely isnt the issue.
Get video or log AFR numbers during these "stumbles". Note RPM, PSI, and most importantly the AFR number. If you are dipping below 10AFR, you most likely have fuel enrichment issues.
The Alpha stuff is sure pretty! 
You might want to throw a hefty zip tie on your wastegate vacuum hose so it doesn't blow off over 15psi. 
That will happen. The breather side doesn't do anything to regulate boost unfortunately. This is probably the #1 mistake made when people have blown motors.
It is good advice and maybe should be in the instructions to remove the fitting from the breather side so that a person couldn't attach it wrong.
It is also important to check that wastegate line periodically even when it is hooked up correctly. A good tight zip tie should be used, but there is still a lot of heat in the area.
What is your plan for a replacement motor?
Running an innovate gauge from DDM. Measuring AFR and boost. Running a V2 1320 header with Alpha side exhaust. O2 bung was welded by Alpha in the side exhaust about 6-7 after turbo. Running BoB tune. Vacuum is t'd off by intake. No leaks that I can see. Highest I have seen is 7.2
Something doesn't add up here. Check your header flange bolts to the turbo and the bolts from the hot side of the turbo to the side exhaust. Make sure they are all tight.
If everything is tight, switch to a green spring and see what PSI you hit. You should be fine if you have ARP studs. Just don't lug it and make big boost at low RPMs.
@Switchblade Are you sure you are only seeing 7psi of boost with that wastegate spring combo? Most of us with the combo are over 9psi.
What boost gauge and exhaust/header are you running?
The next step is to throw a green spring in the wastegate and see what happens. Make sure all your bolts are nice a snug and watch your AFR numbers closely.
With green, you should be seeing at least 10 psi.
It is a precision turbo. And its a 55mm. But it is a different turbine housing. I don't have the last 2 numbers with me....
It is a 5558 Precision Turbo.
But each one is machined/ported to their specs in house.
The Alpha system is very similar to the Hahn. Not sure on exact turbo for Hahn, but Alpha runs a CEA 5558 Precision. Both run Tial external wastegates (39mm). Alpha runs a Tial 50mm BOV, which some Hahn kits chose a different option (for sound?).
The Alpha kit with their header flows a little better than the Hanh kit. Mostly because of the header design and the relocated throttle body.
Both kits on a good built motor will make very similar power. All side exhausts are killing power somewhat. Mine will always dyno lower than I "race exhaust" system, but I can't handle to loud exhaust all the time so I'm cool with that.
The CEA 5558 is rated for 590hp by Precision. So, with the right motor and setup, you could make mid 500s.
To drive around at this number you would probably need the below....
A good built motor
Larger injectors
Fuel rail
Metal intake manifold
3bar sensor and tune
2 stage colder plugs
Tires, lots of tires
Etc.
On stock motors and the major turbo kits, most people were doubling hp output at around 11-12psi. When you build a motor, there obviously are some efficiencies you pick up.
Careful in comparing dyno results from different machines, days, states, and dyno type. It's somewhat misleading if you are trying to apple to apple data.
Wish I had more E85 options by me. I'd love to run some cooler fuel on the stock engine and push some more boost through it...
Have you tried contacting local schools/colleges that have Auto Body programs?
Sometimes they will do jobs for very cheap as your vehicle would be canvas for the students to learn on.
Usually the instructors make sure you get a quality product back.[/b]
Roger that rabtech. It's too hot and I'm too busy remodeling a new house to mess with my motor.
But, there may be a point where I buy a junk yard motor and get after it.
Looks like fun! Can you give more details on the below?
What injectors you are running?
Spark plugs?
Wastegate springs?
Boost and AFR logs from dyno pull?
The type of dyno you guys were on?
I really enjoy following and look forward to learning more about how this engine made this kind of power.
1) Make sure all three hood pads are secure and the center bracket isn't bent2) Refrain from slamming the hood
3) Replace said screw with one that has a flatter (thinner) head
4) Inspect motor mounts
5) Check hood hinges for proper adjustment
These are just a few off the top of my head I'm sure others may have more suggestions
I also cut a small piece of self adhesive felt pad and placed it on the new smaller screw head.
Now, even I it does slam and hit, the valve cover just gets hit be the felt. No chips or scratches for this guy.
Look for these adhesive felt pads at Lowe's or Home Depot is the furniture acc. section.
They recommend farther back because it is hotter as you get closer to the turbo. This means your wideband sensor will likely fail quicker from extreme heat because it is so close.
Not much you can do in your situation. Run it as far back as possible and realize if you get weird readings down the road that you toasted that sensor and need to get a new one.
Anywhere 6-12 inches after the turbo.
Put up a picture of the exhaust and we will point out a good place to install it.
It is always a Desert Eagle, but the caliber picked depends on how bad the area is I am traveling to. 
Jumping without a parachute isnt new, but hoping a net will catch you is!
Travis apparently got in a bunch of trouble doing this several years back. I am sure this guy has all his "permits" figure out if it is going to be on TV.
The belt can be aligned. It is possible that yours is riding too far to the right (passenger side) and it is rubbing on the edge of the rear pulley/sprocket.
Put the machine in neutral and push it down the road to watch how the belt is tracking in the rear. If it is really tight on the right and doesn't have at least a penny on end clearance, you probably found your problem.
Get it it a shop before or after the ride and have them align everything correctly and adjust belt tension. I doubt you will blow a belt in the next few hundred miles, but it needs to be addressed at some point.
Show us how the belt is aligned on the rear sprocket. It would appear it is miss-aligned and rubbing there.
Wrap = less expensive and can be peeled off; harder to apply and best on non-complicated items
Hydrodip = use where you cant wrap or you don't want to worry about the design peeling off; less design options
Wrap items like the nose cone, camera housing cap (base model), and rear plastic mud guard.
Dip items like the belt guard, gas cap, roll hoops, and hood vents.
If you aren't worried about price, I would take off all the pieces together and have them dipped and then cleared over. It lasts a long time and if all pieces are done together (same patch) they should match really good.
Wrap = better pricing and better for people that want to change their look later
Dip= more expensive, more durable, but you aren't going back to the stock look
