i had a set of those bilsteins as my first set of lowered springs and things, they were fine, did the job. nothing too amazing but for the price they seemed like the best on offer. a friend bought some of the viper shocks etc from venom but i wasn't too impressed.
but the boge set have a good reputation, you can buy the whole kit from german and swedish. i'd always buy shortened dampers as well just to be on the safe side.