I have installed a Screaming Eagle Stage 1 air cleaner and Khrome Werks mufflers. This mod really increased the hp and torque. It dynoed at 64h.p. and 88 ft. lbs. I rode her from Wyoming to north of Seattle in 100+ heat and had no problems for 3000 miles. I also have a Billet Cool oil cooler which kept the temp during the hottest part of the day below 205. Great ride for anyone thinking about getting one. I have 20K trouble free miles. The only drawback with ALL HD´s have the oem paper base gasket. This allows a little weeping on the left rear corner of the jug. No worries or drips, but a dust magnet.