Hi guys i had no4 coil go on me today and of course it was one under the plenum chamber.all very easy to do if u have a bit of spare time on ure hands on a saturday it took me about one and a half hours the only difficult part was loosining the two 10mill nuts on the back rubber mountings.the coil cost 31 plus the vat .could have got one cheaper but out of stock.while ihad it in bits i took the time to get the cam belt looked at for ware.for a ten year old belt with 29000 on it it looks great.