Which Year S2K is the best and why?

As always, test drive and you'll have your answer.
You don't learn preference from others. You don't answer questions of preference by polling. You determine these things by experience.
Further, "best" is always highly subjective no matter what the topic. If you want feedback on what's best for you then you need to provide specific info on your needs/wants/preferences/expectations/budget/etc. There is never a single best on any topic for every person out there. Best will vary from person to person since people don't all have identical needs/wants/preferences/expectations/budget/etc. Questions like this are pointless without that information.
Many many more. Threads asking common questions about preference without the OP providing any information for recommendations happen all the time on every discussion forum site out there. As long as there are people there will be questions like this. They're nothing new. You're just noticing them more for whatever reason(s).
Actually many consider the 04 - 05 the worst year to own. It is the softest of all the S2ks and on a dyno you do not see the gains of the 06 up (No flash tune). So even all that torque and the broken gas pedal of the AP1 it will dyno the same once it has Intake, header, exhaust, and a tune as an AP1 with the same mods. What I hate about all AP2 is the shifting is constant. I enjoyed having 200 plus hp from 7400 rpm to 9100 rpm in my AP1! Not to mention the faster rack, stiffer front bar, more lift throttle oversteer, lighter weight, and did I mention the 9k redline!









