I believe Revshift make a relatively affordable adapter for the stock exhaust manifold. I'm not sure of the price, though, and their site says they're not taking any new orders for manifolds right now. Looks like you've listed the 2 major options (524 and Ebay). I've heard bad things about the ebay ones (fitting) some fit, some apparently don't fit at all. Either way, they're going to take some work.

Let me know if you find any local 524TD manifolds

- James