remember theres other factors such as traction and handling, weight (baring in mind his has 4wd so will be able to get traction alot better).
a k04 will proberbly see you up towards the 300bhp mark, if not maybe break it. as for prices ask toby he recently got his k04 running. costs alot though, not going to post it in here as not sure if he wants everyone to know prices ect...
but k04 conversion isnt just a simple bolt on job, unless you go k04-001 which iirc will only see you around 10-15 bhp that k03s. for a k04-025 (i belive it is) you need (i could be wrong on these) throttle body, new manifould, injectors, turbo and associates oil lines and other associated parts for the turbo, usual stuff such as turbo intake pipe and possibly down pipe. but as i said i could be wrong on some of them so best checking.
