Akrapovic makes really nice exhaust systems. It comes as little surprise then that Akrapovic's Ducati Panigale exhausts have won recognition with the Best of the Best Red Dot Award for 2014.
Akrapovic won the Best of the Best in the Product design category thanks to its Evolution Line Titanium full exhaust system created for the Ducati 1199 Panigale.
Akrapovic beat out over 4,800 other products from 1,800 manufacturers from 33 countries in order to win the prize. You can see the exhaust system at the Red Dot Museum in Singapore, and it will be included in the Red Dot Design Yearbook 2014/2015.
This exhaust was made for the 1199 Panigale, but I would guess you could use it on the 899 Panigale as well. Correct me if I'm wrong.