Im not seeing anything worthy of note from those pictures to be honest Mick, Maybe it is simply head seal failure and nothing more...

With regards the cometic, the choice obviously is yours, seems a few people are having issues with them at the moment but i stil stand by my decision to use one and have had no problems with anyone elses gasket and know people with high power YB's also using them with no problems.

I dont think they are quite as good as the Mountune 4layer granted, but they are certainly 100 times better than any fibrous compound gasket like the YBO611.

The studding arrangement i chose again can be argued till we are all blue in the face but ive used them countless times as have many other people and again, ive never had any problems with them. As Karl noted, i would have liked to have known the yield of the nuts /studs but its too late now.

The slight detmarks around the squish area may be due to either a bad batch of fuel, the oil ingress noted already or simply be evidence of the 2 mapping sessions this engine has had in its 2 different specs where its been brought to det to find its limits. It is very light and certainly hasnt been prolonged / damaging det during everyday running.

Id like to see the gasket itself if possible to see thios distortion as it may be down to the seal as you seperated the head and block where one side was simply stuck to the head and the gasket was in fact warped by your removal of the items.

Other than that, theres nothing at all to see from these pics other than shes remarkably clean internally for an 18mth old 6000mile engine on 750cc injectors.

Speak to you soon im sure.