Fair enough. I have done 8+ M54 cylinder heads. I use an old school guy in my area who is great. He also doesn't have the jig (so he says) to pressure test my M54 heads. But he does know how to inspect them visually for cracks - which are typically visible.
He will then test valve sealing on my heads and repair them when necessary. A skims cut of the surface and I am good to go. Usually less than $200.

Cracks do occur on these heads, but I have yet to encounter one on any of the heads I have done. In an overheat they will warp before cracking. I have seen burnt valves and melted pistons.

I usually put a (cheap) straight edge and feeler gauges on the head to see roughly where I am at for warpage before i bring it to him, but if I am warped more than 11 or 12 thousandths (about a third of the time), it can't be saved with a simple surface cut- in large part due to the fact one or both cam lines are also almost certainly warped by a similar amount. The only way to save a cylinder head in this case is to fund a machinist who can bake it an oven back to shape. This is usually more money than the head is worth.