I can answer this one. First of all, Don't! If your seats are still new, exchange them for narrower Sparco models, like the Evo. The Pro2000 is too wide to fit in the car without modification. I've already gone the Pro2000 route so I know what I'm talking about. If I had it to do over, I'd go with a narrower seat. Its not a huge deal but you have to dremel off a bit of the shoulder 'wing' in order for it not to rub the inside of the door.
As far as brackets go, this should apply to all Sparco seats. I got the Sparco slider bracket because I still wanted adjustability fore/aft. To mount the slider bracket to the seat, I had to use some big flat washers to shim it a bit. Email me if you have questions. Then I bought brackets from a certain Viper parts supplier that I'm not happy with at all. Talk to Brian Nightingale at Racecraft. He makes a bracket for the Sparco for the Viper that looks pretty good - much better than the set I got. He can also answer any questions you might have.
http://www.racecraftltd.com/home.htm
Ph: 602.272.6990 (Its in Arizona)