In my opinion, building a fast harley is no different than building a motor for a race car. You really only have two options; HP or TQ based build.
That said; a good HP motor makes power at higher RPMs because the cams (and everything else) are designed to "anticipate" moving fuel efficiently when the motor is really spinning up. A good TQ motor makes power at much lower RPMs by design. If you are going to use the bike mostly for drag racing, then HP is definitely the way to go, but riding in tight twisties and traffic is gonna make you hate the motor. If you spend most of your time riding at 200-4500 rpms, TQ is definitely the way to go.
Any combination of parts you use are aimed at primarily HP or TQ and some attempt to get a reasonable combination of the two. The Most important part is "HOW you ride" and a "good Balance" of the parts you use. I've seen a lot of diappointed people who combined parts that don't compliment each other.
My advice is; first "pick your Power Range", then do with combinations proven to hit that target... But, even the Best tuner can't get a good tune unless the parts are in agreement...
jimbob