So I did this repair yesterday and just thought I would do a quick review which might help others with this. My parts list was about $200, which included the black crossover pipe, small rubber hoses, thermostat, manifold gaskets, throttle gasket (not used), rubbery egr gasket (not used) and two jugs of Subaru coolant, but NO sensors. I should have bought the rigid egr gasket which connect the vertical pipe to the egr w two bolts. The repair took me 5.5 hours, which includes a lunch while the radiator drained out. I was working on a hoist. Subaru says I need the coolant sensor KA140, which is the more expensive one. They did not have one in stock. The one special tool I recommend is long plier designed to remove the rubber hoses - they are hard to reach. All the bolts are 8, 10, 12 and 14mm.
The main thing is that you should separate the manifold from the silver fuel lines assembly (4 bolts) which run in the front and down the sides in an area under the intake manifold. I am NOT talking about the fuel rails which connect the fuel injectors, I did not touch those. Do not loosen or remove the fuel lines or rubber connectors, they are flexible enough to hinge up out of the way. You will take out two bolts so the egr is free of the pipe which runs down to the exhaust manifold area - the little gasket will fall down (it is hard to reassemble, I held it with needle nose pliers until I could get the first bolt started - buy a new gasket, and maybe a spare). Once you get enough vacuum tubes and a couple electrical connections undone, you will be able to tip the manifold / fuel lines back and lift a little. At this time, remove the right side bolt on the fuel line bracket which is hard to reach behind a/c component - the one on the left is super easy. Now wire the manifold back out of the way, and lift the fuel line assembly enough to access below it, but no so much as to twist or tear the rubber fuel lines you are hinging on. You do not need to remove the throttle or the egr valve, just move them with the intake manifold as a whole.
Now is a good time to drain the radiator fluid.
You should now have pretty decent access to the black crossover pipe, which runs left to right directly behind the alternator. It connects 4 rubber hoses, which you should replace (except for the large one in the rear which runs through the firewall - this is where the special pliers will help) - dont cut or damage the original. For the record, I did not see a significant difference between the original and the remodeled crossover pipe, it must be subtle.
On reassembly. Replace the 6 intake manifold gaskets. As you are lowering everything down into place, be sure to install the fuel line screw (front right) while you can still reach it. Lower the whole assembly into place and drop a few bolts into the manifold holes. Before tightening down the manifold, be sure to get that pesky little egr gasket back in place. After that, the rest of the assembly is pretty fast.
I replaced the thermostat, which of course drained more fluid. My refill was just under 6 qts, but I expect to top it off a little today.
So, just plan on plenty of time, don’t drop anything into the engine holes, and make sure to properly “burp” the coolant system by following Subaru’s instructions in the official manual.
I hope that helps someone. I will post a photo from my desktop in a little while.