Anyone have some experience with the expense of replacing the headgasket on a turbo 230bft? My #1 sparkplug is brown, and all the others are normal white. The #1 plug was very difficult to remove as well. I plan to do the work myself, and am experienced at it, but not with this engine. I will send the head to a local head/machine shop for cleanup and evaluation, but beyond that, what does the average headgasket job go for, in the way of parts and time? Thanks in advance, Fred