Hope you have a fire extingisher in the garage and is handy. Those are vacuum lines and no fuel should be present. # 2, should be 8 of them and they appear to all be going to a common chamber so you should have a solid vacuum signal. That is what jffr refered to in a previous reply.
# 3 is the adjustment for fuel pressure and does NOT need to be adjusted. The hoses appear to be hard plastic and may damage the end trying to get it off the regulator. You are not apt to find hose like that easily. The fitting on the regulator is a barbed adapter. It is slightly tapered on has sharp edges around its diameter to grab the hose. You may not want to take it off and damage any thing. Pretty obvious you have a vacuum signal to the regulator. You could try to ID the brand and part number off the regulator and go read about that regulator and see how it works. With a vacuum line reference I think the pressure should vary with load. There is no other reason to supply a vacuum reference. The specs may say "vacuum/boost rise ratio 1:1" , that means on a boosted engine 1 pound boost raises fuel pressure 1 pound. On vacuum it is around 2 inches HG (mercury) to equal 1 pound less fuel pressure.
The sudden lose of fuel pressure would lead to hard HOT restarts. Without pressure the hot fuel can boil in the fuel rails and when you try to start, the injectors and fuel lines have vapor rather than liquid fuel. At this point we don't know if that is related to the problem or has always done that but no one noticed. Again in theroy it should hold some pressure for hours.
You should try a phone call to the guy that tuned the car and hope he can / will answer a couple of questions.
A fuel pressure regulator is about $150 for a house brand (summit racing) to $350 for aeromotive brand , so determine that really is your problem rather than throw money at it.
I said before no hands on expereince with a system like this but have read about so I am not selling myself as a expert.