Its not difficult just very very fiddly as you've got 1.5-2 inch of room to do everything in thats all, forget about torquing anything up as you just won't get a torque wrench in there.
Tools can be hard for circa 50 notes off the net and are essential, the cambelt kit is £140 or so trade off the top of my head. Don't forget the core plugs for the end of the head and the upper/lower inlet gasket if you want to do it 100%.