I used to beat my cars real hard. 428's, 455's, big nitrous kits, no body rips at all. No slicks either though. Always bolt in frame connectors. I think that most of the cars that get body damage from torque have a weak part that is overlooked. Don't build torque monsters out of rusty/weak bodies.

QUOTE;"I'm still looking for a sturdy but not so surgical/invasive subframe connector that doesn't look like an iron bed frame stuck beneath the car."

I don't mind the square ones that you can see. They give you another place to use the floor jack or jack stand. You need to put traction bars on there anyway. You are going to notice the traction bars so what difference does it make that there is a frame connector showing a tiny bit?
To address the bolt in versus weld in. If you drill the holes very close to the diameter of the bolts, use two on each end, use the correct fine thread bolts the right way, bolt in work just fine.