We all have heard people say "Im 6 foot tall i wont fit in a swift". I have always thought that the seats sat too high in the car, with a racing helmet on i only had an inch between the helmet and the headliner. I then decided to lower my seat after searching for hours on lowering the seat and aftermarket seat installs and not finding anything on the topic. All you will need is some scrap metal a welder and a six pack and a day to do it.
The first thing i did was to take the seats out of the car and pull the carpet back over the rear seat. I ended up having the take the rear seat out of the car so to save some time i would just take it out along withe carpet. I wired in my amp that runs my speakers under the pass seat due to the lackof room under the drivers seat.

After removing the seats and carpet, i put my seat back in the car with the original brackets that i fabricated to install the aftermarket seat. All to make my marks on the unibody cross support the at the seats mount to.

I then cut two notches in the cross member, and cut out two flat plates out of 1/8 1.5 in flat plate. i fabricated three pieces to tie the cross member together to maintain the stength.

Then taped the two plates to the cross member, then installed the seat in the car for the second time. with the seat rails sitting in the notches sit in the seat and adjust the position to make it comfortable and take note that most aftermarket seats are wider so it will squeek one the door panel if moved over too far. when it is where you want it have a fraind mark where the bolt will be, if you don't have anyone close it gets interesting quick. then take the seat out again, then drill a hole in each plate and weld a nut on the backside.

now comes the welding of the fabricated pieces to the cross member, now remember to keep the heat on the thicker metal so it don't burn through.

Now that the front has been lowered time to go to the back. the first thing is to remove the tar like mat. the best way i have found is to put ice in a grocery bag and wait till it gets cold and it will chip right off.

The factory seat mounts will simply not work as they are too tall, i took my hammer and in two swings the mount was barly hagin on, this is not the best way to remove the driver side rear mount but after a few beers and it sounded like a good idea. for the right side rear mount i used the better saw's all idea and it worked much better. cut the mount as close to the tunnel as posible. In my case the tunnel was preventing my rail from setting all the way down which the hammer fixed.

now for the rear mounts i used the 1/8 steel strap and made a 90 degree bend for the right rear mount again with a nut welded to the bottom of it. I put a plate on the front of the right rear mount for added strength. the driver rear mount was made with the same idea but there has to be a notch in the corner for the wires the go to the back of the car.

after all the fabrication is done spray it with some red paint or primer. after the paint drys put it back together reverse of the disasembely. My seat came out 1.5 inches lower and it feels like a bigger car because i cant see the whole hood. in combination with this you might want to lower the stearing wheel by putting nuts between the colum and the mount bolts. there are more detailed pictures in my album.

I hope this helps for the people that rub there head on the headliner.