Got it worked out. Part of the radiator mount has to be cut. This isn't mentioned in the documentation, because there is no documentation.
Before:
After:
With this done, the intercooler lines up perfectly.
On to the next challenge: replacing the crappy mounting hardware that comes with it. The included screws are the correct 6mm diameter but a different thread pitch and too short. The correct screws would be part number 17117536972, which are the same thread pattern as the original mounting screws but 40mm instead of 20mm. I did not of course have those handy, so I tried what was available from Lowes. My options were #12 (7/32", 5.5mm) and #14 (1/4", 6.2mm). #12 was a little too small for me to feel secure about it. #14 was a bit too snug but workable. Both of these sizes have the same thread pitch as the screws VRSF provided, not the same thread pitch as the original BMW screws. I used #14 x 1.5", with fender washers and the thick rubber washers included with the intercooler. This produced a secure mounting with good shock absorption.
My main problem is that the thread pitch does not match the original; this situation can cause premature degradation of the plastic if the intercooler is removed/installed repeatedly. I'll probably grab the correct screws mentioned above, to use the next time I pull this thing off.
Finally, the hoses and hose clamps. That all went fine except that the hose from the turbo outlet to the TMIC inlet was about 1/4"-1/2" too short for comfort, so I was barely able to establish a secure seal.
The build quality and fit of the intercooler itself is fantastic. I'm genuinely perplexed by VRSF's decision to stop at 99% by leaving out documentation and proper mounting hardware. Omitting these simple, important, zero-cost details sabotages a great product by antagonizing customers pointlessly.
I'm also surprised that Tiago was unable to understand the problem and explain the solution, given the explanation and pictures I provided.
One other installation note: after removing the cooling fan and before lifting the intercooler into place, loop a couple of sturdy bungee cords around the bumper/radiator assembly and use those to support the intercooler while you're fiddling with the mounting hardware, etc. This is super important, because handling this 22-pound monster is a completely different experience from handling the 7-pound OEM intercooler.