well, there is a long list of stuff.
break in procedure, as with any major upgrade, should be a good 800 miles.
really with this, if you dont know what it takes to install the pistons, you probably would not want to take on the task yourself.
but yeah, lower cr, you can up the boost. your car will be much more sluggish at low rpms though. a little more info can be found on what exactly piston install requires...
here
here