UPDATE:
They didn't convince me to keep it, I decided to after I understood what was actually wrong, and saw for myself what was really going on and what they did about it.
The trouble was that seal for the windshield was incomplete from Freemont ... upper corner, passenger side... they completely replaced the windshield, replacing the seal. They also, for good measure, replaced the piece of headliner along the A-pillar, and replaced both speakers (even tho they were working fine)... that said, I watched them pull down that spot of headliner and it was dry... that is, very little water got in there, and it all dried up quickly given how hot it was here last week.
It's been almost 4 full days since repair, and it's piss-pouring rain here today - I drove 44 miles in that rain from home to work... zero intrusion of water, and, as it happens, I went to check the car in the parking garage at lunch - dry as a bone... everything else is 100% with the car...
TBH, I'm fully expecting a litany of folks here to be disappointed in me that I didn't return it... to be clear: I absolutely would have done so if it was something worse than what it actually was - it certainly looked worse than it was... that aside, I really do appreciate that in reality, it's some people here just looking out for me, a perfect stranger, who just happens to own the same brand of car. So, thanks for that. I was stressed-the-F-out, but I'm satisfied that I'm good-to-go.