If your a competent mechanic its not that difficult a job!!
I replaced the cam belt on mine (GPX) in October last year. It took a whole day to do but that I had expected!
The reason its so time consuming is because its so fiddly and tight on working space.
A few pointers for you:
1. Jack up the drivers side front and rest the car on an axle stand, remove the drivers side front wheel and inner plastic arch liner
2. Support the engine underneath on a trolley jack and remove the engine mount from the drivers side.
3. Remove the power steering, alternator and aircon belts.
4. Strip off all the plastic covers from the cam belt.
5. Wedge some small pieces of aluminium between the pulleys on the cams to stop them moving when you remove the cam belt.
6. Remove the cam belt and tensioner and idle pulley (if replacing) from the block.
7. Remove the water pump and fit replacement. (Remember to refill the coolant!!)
8. Compress the cam belt tensioner in a vice and use some strong wire to retain it in its compressed position ready for refitting.
9. Fit the new cam belt ensuring all the pulleys are lined up (they shouldn't have moved if you have wedged them well to start with!). I used bulldog clips to hold the belt on the cam pulleys as I routed it around the other pulleys.
10. Refit the cam belt tensioner and once you are happy the belt is in place pull the retaining wire out to let the tensioner, tension the belt. REMOVE THE WEDGES FROM BETWEEN THE CAM PULLEYS!
11. Hold your breath and turn the key in the ignition!! It should start straight way. If it does great, switch it off and proceed to rebuild. If it doesn't start double check all the pulleys are aligned with the marks on the head and crank pulley is aligned with the mark on the block. If they are out remove the belt and get them lined up.
12. Reassemble plastic cam belt casing and refit the engine mounts etc.
13. Kick back with a beer and admire your handy work and think of what mods you can buy with the £500+ you have saved doing it yourself!
Apologies if I have missed anything off the above! They are only basic pointers and going from memory! It was a daunting thought for me when I first realised it needed doing but once I had got started its fairly easy to work on, so long as you have a decent selection of tools you will be ok. I would definitely do it again!
