Ryan, here is the information on the ButlerBuilt seat.
ProSportsman Road Race Seat - BBP-17127-65 (I think this number is for the particular seat size that my measurements required but it may help)(I use the 25 degree Layback. With the layback, it gives the most head room by leaning me back more and I am looking for more of that "greenhouse" space above my helmet.)
Sportsman Advantage Bolt-On Head and Shoulder Kit - ADV-22000-4001 This is the halo unit and the shoulder supports. The ribs are weak and can be easily cracked or broken in crashes. The shoulders are much stronger so these are adjusted to wrap tightly around the shoulders to take the impact there rather than in the rib area.
Steel Seat Back Mount - BBP-2130 This welds/attaches to the roll cage and goes forward to the back of the seat to brace it.
1/8 Aluminum Seat Back Bracket - BBP-2131This bolts to the back of the seat and bolts to the Steel Seat Back Mount that is welded to the roll cage.
I also have two Short Leg Supports - BBP-2461-4001 Left side and BBP-2471-4001 Right side to help control leg movement in a crash. What I have not added is a center support to help prevent the knees from banging into each other in a crash and Butler does not offer one.
The seat can be ordered with a Hans option, which is a recess that is intended to allow the Hans to have more room, at the rear, and not press the head forward. With the 25 degree seat, I have not found this to be needed and it saves about $60 to omit.
I cut out the factory seat mounts that are welded to the floor pan as this allows the seat to be mounted as low as possible. It is sort of like a low rider look but gives the maximum amount of hear room, which I want. I also moved the seat back as much as possible to give more room to exit the car through the window and have no problem doing so. I actually had to add pads to all three pedals to extend them so I could operate them. I added about 1/2" to all of them.
I installed the removable steering wheel at a distance to be comfortable once the seat was mounted and it is important to not be in too much of a hurry on this. I remounted my seat 3 times to finally get it where I wanted it. I even have it layed back more than the 25 degree design as that felt better to me, especially in longer races.
I place a piece of 1/2 inch plywood under the seat so that when it is mounted, it is that much above the floor pan so that it has less chance of deforming and hitting the bottom of the seat in a crash. I use a piece of square steel tube, with to flat steel plates and weld it between the tunnel and side frame just under the seat bottom, about two or three inches back of the front lip and bolt through the seat bottom to attach the seat to the tube. My seat is mounted there and with the seat back bracket and steel mount. One of the things that is important is to be sure that the shoulder harness holes in the seat are at the correct height. It would be worth measuring, with Hans on, and verifying with Butler to make sure they are properly positioned. On my first one, I had to cut new ones higher up but on the second one, they seem to have corrected that problem. I assume that they now understand the Hans issue more than when I purchased my first one.
I hope this helps and will be happy to answer any questions you have. In my opinion, the 944 is a very strong car and provides real protection. Having a seat that can allow that strength to be used and that provides the maximum protection is important to me. I have seen far too many guys with cracked or broken ribs in crashes that did not do much damage to the car to be willing to compromise on my seat and harness systems.
Jim "Big Dog" Foxx
