ok i made another thread asking how to do this but it got cluttered... and after a lot of searching and emailing i've found the answers on what you need and why and whatnot.

this is gonna be mostly talk about sparco but it can prolly safely be generalized into more brands, definitely recaro, and bride.

ok... first off there's two types of seats, if you check out the sparco site they have a buncha info on fitments (fitment chart) and you'll see two types of seats, bottom mounting and side mounting.

bottom mounting is what our stock recaros are, the seat is attached with hardware through the bottom of the seat, this is effective at making the mounting bolt pattern pretty narrow, to fit inside most cars. all reclining seats are bottom mount as well as some select buckets such as the pro2000 etc. bottom mounting requires special "tab brackets" to adjust height.

the second type is side mounting, this is the method of using metal brackets posted on the side of the seat, usually for buckets, this method gives you a good mount of height and caster adjustment because there's a variety of holes in the side mounting brackets that can be mixed and matched to give you the fixed seating position that you want.

now the quirk, everyone wants a sliding seat, if you don't have a sliding seat, no one besides you or your twin can drive your car. so you employ sliders when mounting your car. it's pretty safe to say that all sliders are created equal, it's a pretty standard distance between the mounting points on the sliding rails and they give a lil room for tolerances by making the bolt holes "long" to accept more types of seats, basically they bolt to the underside of the seat.

there is a problem however, it's simple to put sliders on a bottom mounted seat, because most bottom mounting seats are good and ready to accept sliders and still bolt up to the "stock" bolt pattern in the floor of your car. sparco has these types of mounting bases ready to ship.

the trick is getting a fixed back seat or side mounting seat to slide because the nature of side mounting a seat puts the mounting holes wider set than your "stock" bolt pattern in the floor of your car. sparco has no real solution for this because not only would it be different for every car (yes the bottom mounting bases are differnet for every car but are easier to deal with because they're at least SIMILAR width) it also varies with seat etc.

the solution is to go to a place like www.gtfabrications.com and have them make you a custom seat base bracket that effectively takes your stock bolt pattern and widens it, a bolt pattern adapter if you will. and this will hook your seats up to stock bolts and still let you slide it front and back.

so far it looks like bride seats are most convenient, their side mounting seats can be purchased with side mounting brackets already hooked up to sliders and a base just sucks that sparco doesn't do this. recaro also does the same but at a much steeper price.

seats to check out are the recaro spg maybe also known as spgt, the sparco evo evo2 if you're a bigger person, maybe sparco rev (based off evo), bride zeta iii or artis and exas if you don't care about the shoulder bolstering so much.

things to look for in a seat. i've made all these recommendations based off the principle that you wanna find a nice light seat that is comfortable (can only be determined by you actually sittin' in it, go to meets and stuff and check out people's seats) and has all the important support points, lumbar, shoulders (to keep your from rocking) and thighs/knees (to keep you from scootin' around). you prolly won't save any weight by moving to any other type of seat, but definitely don't GAIN any weight by switching seats :\. aftermarket bracketing and what not is heavy but there are options to keep weight to a minimum, obviously getting the lightest seat possible, cf and what not are prolly out of most price ranges, but carbon kevlar and fiberglass are light and accessible. aluminum side mounting brackets are about an extra 50-75 dollars depending on where you buy from and what brand but they are only about 2 pounds for both, that's a big savings over steel... sliders are sliders, but you can also opt to have your custom base bracket made of aluminum and that will keep you from having to go on a diet also.