I wish I had got a base tune before I swapped to the Jardine exhaust system. I run the Jardine with a DynoJet PC-III and a stock replacement K&N air filter. My last dyno run put my at 142 HP and 140 lbs/ft of torque at the rear wheel. I belive that to be about a 20 HP jump from stock, but I didn't get a base line run, so I 'm not for sure.
With triple K&N filters and another dyno tune, there's probably another 10-15 HP available, but my bike is running great right now (except for a flat tire at the moment!) so I haven't went that route yet.