if its 16 valve it should be 58mm but i would check. if you take your wheel off and look at the bottom of the suspension where it bolts on...there will be 2 bolts directly above each other, measure from centre to centre, you should see what i mean as soon as you look at it
as for fitting, jack the car up undo the bolts on the bottom of the suspension, undo the top mounts in the engine bay and the fronts should just come out like that
the rears are a bit different, the dampers are bolted at the top which you get to in the boot, the bolts under like rubber triangle things. and youll see at the bottom where it comes off...when you undo both sides the rear axle will drop so put something to stop it hitting the floor, when it does the springs will come out, nothing holds the springs on there just like wedged in.
only thing you will need is a spring clamp from halfords for like £15. when you take the front suspension off you will have to take the tops off and put them on your new suspension, you need the spring clamp to hold the spring so it doesnt fly off when you undo it.
that all make sence? lol, its pretty simple to be honest and as above its like 45 min / 1 hour job, maybe a little longer if your not sure what your doing but theres nothing difficult so youd be fine