The Stage I 103" kit is a top end upgrade and cam replacement; the stock heads flow fairly well as they come from the factory. Buy yourself a SM, pull your heads and cylinders, buy the pistons, have the cylinders bored to fit the pistons, replace the stock head gasket with a Cometic .030" head gasket, replace the cams with Andrews 54s, add some Cycle Shack or Rush slipons, install the TTS Mastertune (assuming there is a tuner in the area that uses it) or the TMax w/Auto Tune if a tuner/dyno is not handy and you will run circles around a factory Stage I upgrade.
Do the work yourself, it's just not that hard. There are 95" builds making some of the numbers posted here for 103" builds.