are they really required?

took mine out to see one needs replacement. man they're expensive.

 

If the little plateau piece on the bottom is busted,you can still get by with the barrel sitting in the hole of the manifold,to hold the injector up.
Some guys bust those things off anyways as they don't like 20 year old plastic cracking off and falling onto the engine.
Personally I bought new,just because it's me..lol!

 

one of the 3 legs broke at the barrel. i'll do as you suggest. i don't know of a piston engine that has diffusers so i don't see overall performance being affected much by not having them on the secondaries.

 

Most guys find out that the diffuser is broke when they replace the injectors.Either for new ones or recently serviced ones.
So really when you look at it,the new or serviced injector Spray pattern will be a lot better than the old injector,right?.
6 of one,half a dozen of the other.