Bosson exhaust for 1200GS

I have just ordered one of these Bosson exhausts for my 1200. Their ad will appear in the April edition of Bike SA - I received a copy early- and they are charging R1400-00 incl VAT for this. Says it improves performance and also sounds great. I felt at that price it was worth a try, as the other "brand names" are fairly expensive - anybody heard of them/has one fitted, want to comment on them??