Does anyone have any information or advice on aftermarket seats? I'm looking for something a bit more aggressive like this from Sparco:
http://www.sparcousa.com/images/96.jpg

Has anyone installed anything like this? Any reason to do it or not to do it? Are any special brackets or hardware required? Is there a certain size/style that fits best? Any better brands than Sparco?

Thanks for any advice you can offer.