There have been posts on this before. However, depending on how tall you are there is a very simple inexpensive solution-and you get to keep the stock seat. Our CRX has no interior to interfere and a Sparco REV is firmly bolted to the floor. I might add that I'm 5'101/2" and have very little headroom in any of my cars with helmet on, except the race prepped CRX.
This is what we did with the Prelude:
Go to a trim shop and remove seat. The bootom cushion need to have the cover removed and the them the foam. Under that are 2 springs that are bent-have the shop replace them with flat ones. Reassemble the seat and see if you are now low enough. If not it is now time to cut the foam pad as much as you can. My car looks totally stock to the untrained eye, btw.
oam piece that is cut off and the stock springs.

The seat cover will have to be reinstalled so that it is properly stretched-my shop was able to do this without sewing. Total cost of the project should not exceed $60. I know of no rails or kits that mount to the stock seat that will do what I've just presented. You can buy any number of seats and mounts-but to get the lowest position with them means a fixed/bolted to floor install.

Good luck