hey all, sorry for repeating what is no doubt a much asked question
im looking to do an STi conversion of my gen 3 GTB wagon and was wondering if you guys could give me some pointers as to the following

recommendations on where to source a STI halfcut (im in syndey by the way)
are there any year model halfcuts i should stay away from (ie will they not fit in or do they have a known prob)
ballpark figures on halfcut cost
any other parts ill need to get (ie will i need to get a new exhaust made up)
once ive got the engine in and workin what paperwork do i need to do?