I think Schroth says the default point is the shoulder belt anchor.
I was looking at those Quick-fit harnesses as well, and here's what I got: I like the idea of having them use the stock female seatbelt points because of that airbag timing thingy, but the attachment point adapters on the outside ends still need to be bolted in. You're still doing the installation work, but the harness can be removed.
Ultimately, I'd say that they're not worth the extra $$$.
As a side note, I apparently got soloracer.com's LAST SA2000 rated Bell SR-Pro helmet - they've been taken off the site.
