Nothing that requires replacing, very easy to do - BUT - the bolts need to be removed and installed in a specific order, and at a specific torque. So having a low-torque torque wrench is advised, I bought a Sealey STW1012 for these sort of jobs.
Look at page 16 onwards here:
http://www.nicoclub....e/2004.5/em.pdf
I didn't disconnect the throttle body from the upper collector, just masked everything up properly, easy peasy
Worth getting a can of carb cleaner, spray it on, wipe it down then use something like a sanding sponge type of thing just to give the outer surface a bit of a rub down. Finally spray it down again with the carb cleaner and wipe it with a clean cloth.