Boxster S 6-pt harness
 

A few questions: I've installed 996 GT3 seats in my '01 986 Boxster S, which was an easy all-the-holes-line-up swap, and allowed me to plug in the seat belt sensors into the original wiring, though the passenger seat has triggered an airbag warning light. I'm shopping for a Hans-compatible 6-pt harness, and I'll admit to being shocked at the $1040 price tag for a pair of Schroth GT3 Profi II FIAs. I understand that these are a bolt in replacement for the lap belt attachment hardware, but (Question 1) are there lower-cost options that make sense? I assume that I'll need a pair of GT3 Seat Sub Mount Bars ($79/ea), though I've seen others just drill through the floor (yikes!) to install an anchor.
More troubling is Suncoast's warning, " If your 3-point safety belt is not connected, the airbag system may be deactivated. Use with caution, we advise professional installation, and off-road use only."
So...(Question 2) do most track/street users swap in the harness for track days, then replace the 3-pts for normal driving to make sure the airbag is functional? Can both be left in place?
Finally, (Question 3) can I create appropriate mounting points for the shoulder belts on a Brey-Krause roll-bar extension? Should I drill or weld? Thanks!

My 987 is a dual use car, and I have both 3 points and 6 points in it. I use the 3 points on the street. Not sure about the 986, but the 987 has a very annoying alarm that will sound repeatedly if the seat belt isn't buckled, which is sensed by a switch in the seat belt receptacle (the part with the red button to release the belt). I made a simulated belt latch that inserts into the receptacle to silence the alarm while using the 6 point.

Does that $1040 include a special mounting kit or something? The belts themselves are ~ $400. Just because you have a GT3 seat doesn't mean belts designed for an actual GT3 will fit. a reputable race prep shop will be able to mount a generic harness for you, the location of the shoulder mounting points is critical for your safety, and will be different if a HAN's is used.

My 986 has both 3 and 6 point harnesses with Recaro Profi seats. I used the Brey Krause mounting hardware in the standard mounting locations for the lap belts, sub bar for the sub belts and wrapped the shoulder belts around the standard roll bar cross bar.

When I am not at the track, I pull the shoulder and lap belts back through the seat holes and sit on the sub belts.

I used a 3 point belt extender in the standard clip to stop the annoying chime and to bring the 3 point belt up and over the side of the seat.

Most dual use street/track cars have both sets of seat belts installed - use the 3 pt on the street and the 6 pt on the track. If needed, create a blank clip to insert into the 3-pt latch to stop the binging of the seatbelt monitor when using the 6-pt.

No reason to use the GT-3 belts, consider a standard Schroth HANS 6 pt harness like the Profi III for ~$400 ea. (http://www.schrothracing.com/competition/profi/profi-III). This still isn't particulary cheap.

Unfortuately, the only easy place to attach the harness behind the seats in a stock Boxster is the horizontal portion of the roll hoop. This may not be perfect in terms of harness-shoulder alignment but its the only option available and is commonly used in Boxster BSX cars (dual street/track use).

The Brey-Krause rollbar extension mounts above the stock roll hoops so it will not help at all with a better harness attachement point. Creating a custom harness mount that has improved harness-shoulder geometry is up to you.

Wow. Such good advice! Thanks to all who wrote in.

I fixed the link in my previous post.

Schroth has excellent installation instructions:
http://www.schrothracing.com/sdocs/2009_Competition_Instructions.pdf

Update
 

Just back from a 2-day DE at Watkins Glen. In the long run, I realize that I was deluded when I believed my only costs would be the seats and harness. Switching to "bolt-in" OEM 996 GT3 seats required also switching to an aftermarket BK seat bracket, as I was too tall in a helmet, even with the BK roll-bar extension. I needed a BK sub-strap harness bar mount, and had to have Stable Energies, NJ fabricate a bolt-in harness bar with the right geometry. They had Schroth custom-fabricate a Profi II with the correct ends for my seat belt mounts for slightly less money than the GT3 belts. Self-installation of all this was pretty straightforward. My seatbelt chime goes off by itself after a few seconds, so I just left it alone. Everything came together nicely when used with a 20 degree HANS, and the increased safety and firm location seems worthwhile. Still, I'll probably switch back to my regular seats after the last DE event of the season. Thanks to everyone for the useful advice, and to the patient guys at Stable Energies.

Also...Once I installed "keepers" (which I forgot on the first trip) on the harness bar to keep the straps from spreading, I had to remove the storage box above the engine cover.

An add in for those considering harnesses. By mounting your seats to the floor instead of on a slider lowers you about 2" which puts the shoulder straps at the right angle from the roll bar mounting point for most drivers. It also adds 2" headroom to get you below the broomstick rule. This solves a lot of problems if you are like me and never really use the slider anyways.

Yes, many of us have had the same experience - you're thinking: How hard can it be to mount racing seats? The truth: VERY DIFFICULT (and expensive)!

I have swapped to Reccaro Pole position seats. I had a similar problem/ I spent days measuring to drill and additional set of holes in the BK seat bracket to lower them to keep the slider. Finally had to cut off and move the slide release to the center and take some of the bend out of it. I've kept the seats in, and the three point harness for daily driving. I've had back surgery and find the way the Reccaro's cradle you give me a better feeling driving long or short distances.

Was it the October 7 and 8 Niagara DE. If so I was there also.