now cylinder head crack, was exhaust manifold studs

["Colin Barfoot" <Colin_Barfoot@msn.com>]

On removal of the head to drill out the studs and install a bushing to reapir 
the previous bothched helicoil job (before I bought the car) the head was 
cleaned up and a crack found running all the way between 2 valve seats.
It will cost $500 to cut out reweld then machine the head - as well as drill 
the studs.  Not fixing the crack will be <$200 but I don't think thats a real 
option since the crack could allow a seat to drop out and bye bye engine then, 
or it will at least let coolant leak into the engine.
I can buy a rebuilt head from Audi for $685.
Or I can try and fins a used head for $???

What do these prices look like? compared to what others have done?

Does anyone have a better option to offer.. i.e. performance and or price 
wise.

PS this is Canadian dollars i.e. = $.72 US

Oh the ehaust manifold cracks (2)  and down pipe to turbo weld repair went 
well, manifold macing is next.

PS The wastegate diaphragm is cracked, does anyone know of a source for 
replacements?

Thanks for your suggestions and help.
Colin
86 5000 CD Quattro