I thought I'd post a few pics of my recent Tillett install. These are great seats, I love them so far! I picked these up because I wanted to run 6-point harnesses with my HANS device but I also infrequently drive on the street, so I wanted bolsters low enough to run the stock 3-point belts simultaneously. The B5 is also HANS compatible.
The brackets that Tillett sells don't allow use of the sector111 hardware, so I picked up some bushings from McMaster and pressed them together to keep the belt ends separated and movable.
The bolt used in the Tillett bracket is an M10 (10mm diameter thread); the eyelet for the Schroth lap belt is 12mm; and the eyelet for the OEM buckle/belt is ~15mm. I ordered the following parts from McMaster to create this custom bushing:
<Metric Steel-Backed PTFE-Coated Bronze Bearing, 10mm ID 12mm OD
<Metric 932 Bronze Flanged Sleeve Bearing, 12mm ID 15mm OD
I pressed them together and figured out the proper spacing for the Tillett brackets, then installed them fairly easily. The belts can rotate freely enough, but there isn't a bunch of slop/play.
I also picked up some shaft collars through McMaster: http://www.mcmaster.com/#6436k75/=y0161h
<aluminum, for 1.5" shaft (the harness bar for the track pack on my 2007 Exige is 1.5" diameter)
I highly recommend using some of these to hold your harnesses in place. However, the problem with the track pack harness bar is that the Lotus speakers behind kind of get in the way. I used my favorite tool (brute force) to get the collars into position so that the shoulder straps would line up correctly coming through the seats.
I'll be working on installing the bushings and the shaft collars on the driver side tomorrow, so I'll post some more pictures then. It's far more secure than using foam and zip ties!