I changed mine on my 300D...same engine...it was fairly straightforward...just be sure to clean out the holes that the hex wrench is supposed to go into, you want to get that wrench in there as far as you can....also be sure to note which direction the checkvalves face.
I had to take off the fan and the shroud, along with some belts, so I could get to all of the bolts, and the unit itself. Use a torquewrench when reinstalling it so it doesn't leak.
Have fun, and don't bust any knuckles!
-Larry