BC the Scatt individual heads are apparently no good as they run much hotter due to the vastly reduced fin area. Mosler used these heads apparently, and was a source of one of thier problems. Im not sure why they still make them, as for a race engine, they must kill the engine prematurely if they run them at the max.
Auto d, if the T4 needs too much mods to use, it isnt worth it. If one end of the head push tubes match approx the spacing of a T1, and the stud problem could be overcome, then yes. No..... its back to a good ol T1 head..... If you are talking about new cases etc, its a massive job, and you will probably end up with years of tears and expense..... If you were going to go that route, why not get a Scatt killer case, and build a big bore stroker at 90mm stroke?
If you contact them, you may find that they could leave the studs in the case undrilled, that way you may be able to use T4 barrels and heads? This would be far better route, and one I would consider as the case is so much better than both the type 1 or 4 (but probably heavier. It is a pretty good price however). I dont have enough knowledge of the VW to be able to say what other problems may be lurking if you went this route however?
HH
P.S. BTW Brian, love your 'Flying Rules'! Hope you dont mind, but I nicked them and stuck them on my FB post, got loads of likes!