You will need a pump, a PAS box and the pipes.
I have the 2.5N/A in my 90 and I toyed with the idea of fitting it but I don't find the manual steering in the 90 that bad (as long as you don't try dry steering - teaches you good steering in my opinion!). Anyway there is a little metal plate bolted to my engine where the pump would bolt on, so you need to get these bits, if your handy with a welder and around the workshop you can make the brackets etc...