[mapt]

The way it was explained to me early on was that the newest Raptor engines had simply eliminated many of the different types of test sensors, specifically because sufficient testing had been performed that they weren't getting useful data out of them any more.

I'm not some kind of insider, though.

[kotaKat]

It honestly makes sense now that I'm looking at a progression down the line - https://i.redd.it/f7prq0x08qgd1.jpeg

Just continual tweaks and refinement to keep slimming down the packaging.

[moralestapia]

Hey, where did you get that image from?

First time I see it!

[dotancohen]

That photo is thrown around a lot in the Spacex fan community. At least it was. I think the photo is at least two years old.

I suspect that many of those pipes are for testing instrumentation of the early models. And those that remain necessary, might be built into channels in the engine body now, like how a carburettor is built. That's much simpler and cheaper to manufacture and maintain, not to mention more reliable.