Did you look for a crack? When my 850's intercooler blew a) it was loud and b) the crack was easy to spot. But it was on the bottom so it was right in my face when I had it up on ramps.

I'd lose the tune while you figure this out. It's just adding a variable to a lengthy variable list already. Do you have a friend with a T6 you can swap in known good parts like TCV? That intercooler looks difficult to feel around on, but I'd do my best to get at it and do just that. No gloves. You ...