I have this kit from jre.
http://www.jreperformanceparts.com/g...p-package.html
It will put you at your goal of 600+ hp going this route will cover most of your bases of fuel, boost ect. You'll have it set up already for a bigger lower pulley for when you want to do the cam. I dont have any heat soak upgrades on my car and intake temps are just fine. Best thing I can tell you is give Ted a call and just go over what your plans are for your car and he will help you put you on the right path.
Your boost levels will drop with the better air flow with a cam.
Stock lifters will be fine with a cam, a trunion upgrade would be a good idea.
Heat soak I wouldn't worry about at that HP level. Would it help sure but you wont gain very much from it.
Also I can't blame you for wanting to do just a cam nothing beats the sound of a cammed LS.