I'm interested. I have a full Akra system on my R1200S. Supposedly BMW Motorrad shares engineering with Akrapovic for development purposes.
The R12S system cost a small forture... Fits great, runs great, sounds great, but was far from cheap.
The Akra system on the HP2 Sport shown in this picture retails for $4-$5K!! (granted, world market is very small on HP2S upgrade exhausts)
