nothing different between that and the Akrapovic full system exhausts that have been available since the bike was released. removing the db killer won't do much for power at all. the main power restriction on the HP4 is in the midpipe. you'll have to replace that with the basic unrestricted midpipe in the regular Akra full systems, and there's surely 5-10 more horsepower to be had with a PCV...the HP4's peak power is rated the same as stock, although I'll bet it dynos out a little higher.
2012 S1000RR, sapphire black, DTC and HEATED GRIPS
2014 Ducati Multistrada Granturismo
2011 Ducati Monster 796 ABS
2000 Ducati ST4 (sold)
2010 S1000RR (sold)
2007 F800S (sold)