1)No its not true, the more HP you start out with the more you'll have in the end.
2)Depends on how much boost you run. The B16 will make more in the end.
3)I'm pretty sure it doesn't swap back and forth.
4)
http://www.hondamotorsonline.com/sho...DM% 20Engines
Rebuilding an engine can get pretty costly, pistons like $500(plus labor), rods like $500(plus labor), sleeves 800-900installed.
But then it'll be rock solid capable of 20psi or more. A good turbo kit is about $3500 or so.
It all boils down to how serious you are, and how deep your pockets are.