Update: while I bought and installed the Sector111 4Tress bar and am happy with it, I removed the anti-submarine strap I bought from them b/c (i) there's insufficient clearance between the bar and the bottom of the seat once the straps have been attached (this forces the bar to bow out from its mounting bolts even with spacer washers inserted and bind against the brackets that secure the strap to the bar) and (ii) I didn't like how the bar attaches to those bolts (the ends are simply bent in a big loop, secured by big flat washers and nuts).
I'm sure from a safety perspective, it was fine, but my buddy, Dave, offered up a better solution, and I thought I'd post some details about it here. Dave makes custom bicycle frames, but he also has a thriving business doing various car-related parts, mostly for NSX's. You can find him and some of his stuff on NSXPrime.com under the screen name "TitaniumDave".
Anyhow, below is a photo of the anti-sub bar that he made for me. This one's a beta, so it hasn't been painted, but I find it altogether a better solution than what I had. If anyone's interested, Dave can be reached at
TitaniumDave@msn.com. I'm sure he'd be happy to make more of these now that he's broken the code on how to do so. You'd have to negotiate the details with him. I just thought I'd share what he's done with the community in case someone's looking for a better way of securing their sub-strap.
Best,
Twin
.