i personally haven't bought anything from him, but i have heard nothing but bad rep from friends about him. i've heard he's a crook but like i said, this is all hear say.
i can however say that the swap to a 3.4 will be a much better option. i spent well over 2k doing a rebuild, port with larger valves, intake mod, exhaust mods, and can honestly say that there is a noticeable difference.. but not 2k worth of a difference.
put in a faster muffler bearing, it will double your horsepower.. and neon lights under your truck will give you more torque.