Low boost after turbo change - suggestions wanted

[93VSpec]

Some quick background: I have just finished installing new turbos (Garrett GT2860R) and installing new coolant hoses on the intake side of the engine, during which I had to remove my intake plenum.
Now the car drives fine up until around 4800 RPM, and about 9 psi, but then the engine seems to bog down and stop increasing RPM or boost. Wideband sensor also drops off the charts (less than 10). Before the turbo change the car would hit around 14 psi without a problem.
With the windows down there is a very obvious compressed air sound as the boost increases.
I have my own thoughts on what it might be, but was hoping to get some feedback here. Any help is appreciated.

[judasentinel]

With better turbos and afr still dropping below 10 while under load, I would look into the possibility of a boost leak or inadequate spark. Its either electrical (tps, ignitor, coils, spark plugs, wiring, etc..), or you have a leak somewhere. It is very much possible that some vacuum line under the intake plenum is messed up.

The above is just an idea. There could be many other things as well but lets eliminate the obvious first.

[gtrjerry73]

Also if you are still running stock coils they are apparently only good for around 450 horse. Same with your injectors. Stock fuel pump maxing out? You may even be maxing out your mafs not sure what kind of power your making but it's a possibility. Higher flowing turbos don't need to push as much boost to make more power.

[93VSpec]

I'll grab the propane torch and check for vacuum leaks.
I forgot to mention that I also removed my charcoal canister when I had the passenger side of the engine apart, and plugged all of those hoses.

[NismoS-tune]

boost leak for sure. On the same turbos I make 1bar at 3600 rpm.

[cortexx]

leaky BOV ?