Hi just been reading the posts, I am not trying to put you off but after nearly 16years in the trade I have had to "repair" alot of DIY jobs. A headgasket Can be quiet major depending on the age and type of car. Haynes manuals are ok for a compatant person who does have a good idea of engines, BUT the thing they dont tell you is WHAT HAPPENS WHEN something goes wrong. I have yet to find ANY garage that cant deal with or dosent have the equipment to deal with such a problem. If it was break pads, rear shoes, simple service then I would encourage such a thing but a head gasket I would strongly advise to leave to the professionals. Yo give a quick simple example, we had one in a few years ago that didnt realise that the engine needed a support before removing the head, what should have benn around �300 ish cost nearly �1000. Please be warned, I dont want you to have to waste money!!!