I briefly considered them (they also do a 4-way version too) - have a look at http://www.a-pp.com/piaa.htm as they were pretty ok to deal with and have a 'bargain' section too.
Figured the lights were just too big to mount anywhere on the GS without obscuring something (indicators...) or limiting the light pattern. Also bl**dy expensive. I'd rather have fitted a dim/dip light but couldn't find any small enough that would suit.
Have bought 2 sets of spots from the 'bargain' section (1 pair dim, 1 pair main). Work fine, not too obtrusive and have a great light spread.
Only place i could see to mount these lights would be crash bars and mine would have needed modifying to permit that. All in all thought it was way too much aggro/money.