I've only ordered one part from them - a 4 into 1 exhaust for my Kawasaki Zephyr 750. The process was painless but the product was total crap. Badly welded, header pipes that were misaligned and the rear bracket was in the wrong place.
I asked for a refund and never heard anything back from them, so I won't be using them again.
I think they act as a kind of broker and just source parts from suppliers around Japan.