I believe that you CAN build a reliable 120 hp, 103 motor. I had my mods done one year and over 10,000 miles ago...it runs strong, smooth, and is very reliable with absolutely no problems to date...and I run the hell out of it. I've ridden it around town, around the state, and to the mountains and back...and I wouldn't change one thing about it. It's not exactly 120 hp, but it is dang sure knocking on the door if it, and about as close as you can get without being there...it may even be there now...the chart below was made at the 500 mile break in. Green run = baseline after the build with Rineharts and standard baffles...Red = immediately after changing to the larger performance baffles, and Blue = final run after dyno tuning. This motor started life as a stock 103 motor in a SERK...the numbers prior to the engine mods were 89.5 hp and 94 tq. They are all bolt-on Screamin' Eagle parts...details of what's in it are listed in my Homepage. Would I do this exact build again? Hell yes.