What you listed for the most part are not modifications for power, rather for reliablity. The power is in the turbo, intake, fuel and exhaust systems and of course a good tune.
yes a ka-t will support. Ka’s have supported as much as 515whp on a stock block with a cometic head gasket. How long that motor will run really depends on how well of a tune it has. All the parts u mentioned are great to get. But like mentioned u need the fuel intake and turbo to support all of it
www.ka-t.org is all you need. This site tells u everything u need for a turbo ka.
I would also recommend figuring out what kind of compression ratio you want. As the higher the compression ratio the more chances you blow your bottom end. If you go too low of a comression ratio you loose your initial torque. The turbo helps in the long run when it has had a chance to kick in. So make sure you do your research. By the way I would not recommend changeing all that at once. I would suggest getting another KA engine that you can bolt on the turbo and get a feel for it get your turbo setup done. If you are willing to take your time and experiment on a crap block you will be able to tune alot better and have agood idea of what your results will be it would also involve pulling that crap engine out and putting your good engine in once you have figured out what you want to do. This way you dont put unnecessary wear on all those new components you are going to be spending unnecessarily. Just a suggestion.
With the amount of money and time you will spend building your own block I recommend ordering a fully built and ready to rock KA motor from AMS.
This way you know what you are getting will work properly and has been proven to be good for very high hp numbers. Not saying you dont know how to put a motor together but home style rebuilds are always risky.