There will be small gain compared to tuning it on the dyno to suit the 100 octane, you can put a couple of degrees more timing into it and then you will see more than just a small gain.
dont know about that... mine made 420rwkw on bf valve springs, the process west cooler is very consistant for 300rwkw using the std plenum and air intake,if you push 350 it struggles on a warm day.
lol Good luck to you in trying to get your goal,it will be a feat in itself, I for one am not game enough to push my 107000km Ba motor anymore than 16psi.
I always thought unopened was valve spring changes too..... and I believe it has been the case on here, dont know where cams and headwork came from..lol