How can you put a 5-6 point harness in a Striker? Where do you mount the lower strap? The seat is right on the floor so how can it be done? Singleseaters must have the same problem right?

A slot is cut in the crotch area of the seat and you need either 2 bushes in the chassis at 100mm centres (6 point) or one in the centre (5 point)

Do you have any pics? Also how do you mount the lower straps? I don't get the picture.

I haven't got any pictures.
You usually use seat belt "eyes" and clip the belts on to them.

I've had this in my BMW, but the eyebolt stands up on the floor. There is no room for this in a Seven. The eyebolt would hit the seat or is there enough room?

If you are using the fibreglass seats in my avatar, the eyebolts will just go under.