Stage 1 power upgrades 4-9 - Evo Owners Forum
Should help with most questions you have.
Regards to fitting parts and mapping, where are you and do you have the parts already?
Evo 4 engine not worth much due to the crank walk possibilities... People scared of buying them...
As rob said they generally dont go for anywhere near as much as newer engines because people are scared off by the horror stories. That said mines done over 120,000 miles and is still going strong.