If i was to pick up a modern non runner, and fix that up, would I require a lot of specialist tools, or just need a decent selection? Like I said the tools I have, allow me to fully strip down and re-assemble a car and components.
Specialist car tools are unlikely to be of much use, although you may be able to adapt the odd item?
The special tools you may need generally aren't particularly expensive items (unless you are thinking about restoring a BMW perhaps?) but you are likely need at least some special tools.
But you must appreciate that until you have more idea what type of bike you intend to restore it does make giving advice about this sort of thing rather difficult, and going into detail over the pros and cons of all the different types could be worthy of an article?
Working on Japanese bikes is normally fairly straightforward, and they can usually stripped and rebuilt with a fairly standard set of (metric) tools (and an impact driver etc.?), unfortunately many Japanese bikes are less 'owner repairable' than a British machine would be, for instance many Japanese bikes have overhead cams whose bearings probably run directly in the alloy of the cylinder head, making any cam bearing repair work a specialist job.
Likewise many Japanese bikes have built-up ball bearing crankshafts, and again they are likely to need specialist attention if any repair work is required, unless you have your own 10-ton press?
Various *genuine* Japanese parts like exhaust systems for instance, can be quite expensive.