Campbell Custom exhausts make twin Sidewinders for the Gen 1 (and Gen 2) http://www.campbellcustom.co.uk/Yamaha%20FZS%201000%2001-05.htm
this might be an option http://www.ebay.co.uk/itm/Exhaust-Danmoto-XG-1-Yamaha-FZ8-FZ-8-Fazer-EX469/160814615573?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D286%26meid%3D8843070054750350526%26pid%3D100005%26prg%3D1048%26rk%3D2%26sd%3D360484715323%26 I don't know if you could get a suitable link pipe, you could try emailing the seller if they could do a matching link pipe, but these pipes are not baffled, and it is in china