The Stealths certainly don’t need $500 worth of labor done to them to be run.
For around $550 you could have a proper valve job done, back cut valves, skim cut the decks....... and have the bowls blended and a flow test done.
But they certainly don’t “need” all that be done to them.

The ootb flow is nowhere near 290. It’s high 250’s/low 260’s.
After recutting the seats and blending the bowls it’s about 280.

If someone wanted to run them ootb, I wouldn’t argue too hard against that.

At my shop, it’s unlikely you’d be able to have a set of 915’s gone through completely, all new parts, hardened ex seats, all new guides, valve job, flat mill, etc, for any less than what you’d have in the Stealths.