Electric racing seats? That is an oxymoron. The idea of racing seats is to reduce weight, whereas electric seats add a bunch of weight. I really doubt there is anything out there that matches that description, but I may be wrong.
If you don't have the sport package, then you can get the OEM BMW sport seats. Getting them from the dealership will cost you a lot of money (by my standards, at least), but outside of that, you are restricted to buying used ones. If you have relatives or friends who can have them shipped to them in the US, you can try to find a set on eBay, such as:
http://cgi.ebay.com/ebaymotors/04-05...QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/04-05...QQcmdZViewItem