Yup there not cheap...or just send your current one off to Owens and get them to build something mental in your current frame. They can literally do anything.
Like said, most probably rings or gasket. do a compression test.. Doing rings isnt to hard to be honest if you take your time. Depends how bad it is and if theyve scored the bores tho. Strip it down and have a look.
It's not a case of them packing up. Nothing wrong with having a stronger more reliable ignition but no it doesn't need to be changed until you start going abit mental.
Lovely looking bay mate. if your staying td/vf flange get a Turbo Dynamics MDX range tubby on there! Oh and we need some videos of this in action haha!
I take the rad out for access. only takes a couple of mins and saves you punting it too. Havent done a standard cat for ages, but i seem to remember a deep/thinner 12mm socket was always useful for getting it off the back of the turbo.