Is it the whole system/halve sytem or slip on end cans?
The answer really depends on your ability with a socket set and a plastic mallet!
They are easy to do I think, the main problem people have with fitting them are lining them up or getting all of the bolts to go back in correctly, as Italian welding appears to leave a little to be desired!
You should set aside a couple of hours so not to rush it, and if you decide to do it yourself, then lots of people (ie hundreds!) have done it before on this site...so the help/tips will be there.
Go on, do it yourself, and save the cash for something else like some ear plugs and tinted visor to hide your big grin!
[Edited on 24-8-2004 by Harv748]