Today (18-02-2006) I replaced my spark plugs and spark plug cables.
This is now typically such a job that is easy to do yourself.

What do you need:

     set of new spark plugs
     set of new spark plug cables
     16 mm. spark plug cap + ratchet + extension

The new spark plugs and spark plug cables:

The tools:

My engine "before". I think three different types of cables...

Where to begin:
Grasp the top of the first spark plug wire firmly and pull it up. They can be quite hard to get off but with a firm hand it should come loose. The other side goes the same. With spark plug cables, never pull on the cable itself, the mantle can be damaged and you can tear it, this causes a short. You will notice this!

Plug taken off. The spark plug is recessed deep in the hole:

With the ratchet and the spark plug cap, to unscrew it. An extension to your ratchet is definitely a requirement! Later I took an even longer one to give myself more room.

The new (left) and old (right) side by side:
(edit: I don't recommend the 'splitfire' plugs. They don't seem to work as well as the traditional type. Maybe it's between my ears but I don't use them any more.)

werkvolgorde:
Handigst is om de bougies/kabels één voor één de doen. Dus eerst de voorste (één) in z'n geheel vervangen, dan de tweede (twee) etc. Je raakt dan niet in de war met de volgorde.
Aandraaien: vast is vast, dus niet te strak. Ooit moet 'ie er ook weer uit!
Mocht je een momentsleutel tot je beschikking hebben, aanhaalmoment is: 15-32Nm. (11-17lbf/ft). Bij twijfel erin draaien, niet al te strak en bij je dealer of vaste garage na laten trekken.

Tip: doe wat kopervet op de schroefdraad voordat je de bougie erin draait. Dan gaat 'ie zeker niet vastzitten.

Nog ééntje te gaan! Voordeel van een "echte" bougiedop (in tegenstelling tot een gewone 16mm. dop) is dat er een rubbertje in zit waarin de bougie klemt. Dit maakt het indraaien heel wat gemakkelijker.

work order:
It is most easy to do the spark plugs / cables one by one. So first replace the front (1st) cable and plug, then the second (2nd) etc. So you don't get the order mixed up.
Tightening: tight is tight, so not too tight. One day it has to come out again!
If you have a torque wrench, tightening torque is only: 15-32Nm. (11-17lbf / ft). When in doubt, screwe them in, not too tight, and have it checked at your dealer or local garage.

Tip: put some copper grease on the thread before you screw in the spark plug. Then it definitely won't get stuck.

One more to go! The advantage of a "real" spark plug cap (as opposed to a normal 16 mm cap) is that there is a rubber grommet  inside which 'grasps' the spark plug. This makes taking them out and screwing them in a lot easier.

Everything nicely tucked in:

The old mess. Three different cables (but still four identical plugs!)

I case you did take everything off in one go here is the right order:

for the 1.6

for the 1.8

kabels van 1 en 4 en van 2 en 3 kunnen evt. worden omgewisseld. Deze ontsteken tegelijkertijd.
you can switch the ends of 1 and 4 and of 2 and 3 (the green end). These ingite at the same time.

Good Luck!

Dennis

With special thanks to (in no particular order):
Cherber, Mxvijftor, Hamer