Hello mate, mileage is nice and low. I'm not sure when the first cambelt change is due (tiag will know) how much is he asking for it? Regarding the bits needing doing your find them easy enough on ebay or "Japanese import cars"web site. The only thing I see you picking up second hand is the cross pipe between the manifolds,what's wrong with the pipe?is it rusted away or damaged .if its been damaged you may want to check around that area.
A tow bar on a gtb no no no .........only joking mate,if you wanna tow caravans at 150mph plus I'm cool with that