not sure on price for fitting of cams, as I do all my own engine work.
but courtenays or regal charge '@£600 ish' to supply and fit, the cams are a good investment for power
the throttle body's aren't made any more, but sometimes come up on ebay
as for the dbilas exhaust manifold, I've seen them fitted to vx220's, but I have no idea who sells them, except dbilas direct maybe