I have an MSM with 155,000 miles on it. It's mostly stock with intercooler, radiator full exhaust K&N. Two weeks ago the head gasket blew. Just got the car back from the small shop it was being worked on and now it's having issues. They replaced the gasket and brought the head back to spec. When I picked the car up it wouldn't get past 5 psi when it normally pulls around 9 in the cold weather we're currently experiencing. No blow off sound just the sound of my turbo fluttering. Can't find any leaks or disconnected or out of place hoses. Was hopping the experts could give me some general advice as to how to proceed.

 

They took your mojo?

 

Considering how much disassembly has to happen for a head gasket. I'm going to bet its a boost leak.
Have you considered doing a boost leak test by pressurizing the system? A cheap DIY one can be made for sub 25$ from Home Depot racing.

It may also not be just a hose connection. Have you considered checking to see if they installed the TB gasket back in place?