Picked up some old Sparco seats for the GD. Here is some info about putting them in as I converted my street car to a track car.
The first thing you will want to figure out is what sort of restraint system you will run. Will you continue to use airbags? Will you use the stock seatbelts? Depending on how much bolster your seat has you might be able to get away with stock seatbelts, but they won’t hold you in place like a good 5-6 point will under high g’s. If you decide to go with a harness system, make sure to get an anti-submarine strap, as you could slide out the bottom of a four point harness in the event of a frontal collision. .
In this case, a Sparco harness bar was selected. Later on, the car was upgraded to an Autopower bolt in rollbar and ultimately to a full weld in cage. You want the harness mounting point to be more or less directly behind your shoulders by about 6-8 inches.
You will also need a seat bracket, side rails and sliders (if you want to be able to adjust the position). Start by removing the four bolts holding your seat to the car and disconnect all the airbag and seat belt harnesses. Some aftermarket brackets include a bracket to re-use the OEM seatbelt hardware. This is useful for defeating airbag lights, which will be illuminated if a seatbelt or airbag is disconnected. You may also need to put a resistor in one or two connectors to fool the system to thinking seat air bags are still connected or position a sensor in such a way that it provides accurate readings on occupants or seat distance.
Once you get your stock seat out, you can install the bracket, the slider and the side rails on top of each other in that order. I usually assemble these items before bolting the bracket into the floor of the car. I also replaced one of the seatbelt mounting points with an eyebolt for my harnesses. I found brackets designed for harnesses in a Porsche and installed them between various seat belts to complete my 5-point harness setup. The last step was to select seat height and angle. You may want to play with this for a while to make sure you don’t interfere with the operation of your harnesses and that you are comfortable driving the car. You will typically will want to be closer to the wheel than you might be used to.
Aside from the improved feel of using race bucket seats, you will also likely save something like 30-40 pounds in weight of the car, which is a great number for weight savings.