Tom,
Please keep us updated. The "auto tensioning" device has been the sticking point, as far as I know. Also, while there is no problem using the stock mounting points to attach the 5 points, I think the problem is REMOVING the stock one - if you keep both, then its OK...
The floor mount is interesting - would you have to route them through the seat back? My only concern would be that in an impact, the seat back would have to be strong enough to absorb the impact without breaking in half or folding forward. Do you have any pictures? I'd like to see an install that did not require bulkhead cutting.
Thanks and keep us updated.
EDIT***
Did a little digging. Text below copied from
NHTSA Section 208
Standard No. 208 -- Occupant Crash Protection
This standard originally specified the type of occupant restraints (i.e., seat belts) required. It was amended to specify performance requirements for anthropomorphic test dummies seated in the front, outboard seats of passenger cars and of certain multipurpose passenger vehicles, trucks, and buses, including the active and passive restraint systems identified below. The purpose of the standard is to reduce the number of fatalities and the number and severity of injuries to occupants involved in frontal crashes. Generally, the requirements are as follows:
Passenger Cars (Effective 1-1-68)
Lap or lap and shoulder seat belt assemblies for each designated seating position. Except in convertibles, lap and shoulder seat belt assemblies are required in each front outboard seating position.
Passenger Cars (Effective 1-1-72), Multipurpose Passenger Vehicles, Trucks and Buses - Options a and b only (Effective 1-1-72)
Passenger cars, multipurpose passenger vehicles and trucks with a gross vehicle weight rating of 4536 kg (10,000 lbs.) or less, and buses (driver's seat only) shall have:
a. A complete passive protection system, or
b. Lap belts, belts warning and meeting 48 km/h (30 mph) crash test requirements, or
c. Lap or lap and shoulder belts, seat belt warning; outboard seats shall have a single-point pushbutton release and emergency-locking or automatic-locking seat belt retractors.
Passenger Cars (Effective 1-1-73)
Requirements same as above except upper torso restraints shall have an emergency-locking retractor.
This last part is the part that disallows the use of 5 or 6 point harnesses as your ONLY seatbelt system in a vehicle.
If used properly, the 5 /6 point is better, but since it does not have the emergency locking mechanism, if someone got in the car, got lazy, and only loosely fastened the belts, or on did a couple of points....... We call that natural selection, government calls it protecting it from ourselves...
Hope this helps.