190e 2.6 injector setup question
 

I've let a 2.6 sit for a while and it didn't want to start. After confirming that it had gas and a working pump, I undid and injector and cleaned it a little. That helped, so I did 3 more. That got the car running.

What seals, if any should be replaced when remounting the injectors?

There's a pair black plastic bits on the injector.
There's a white plastic receiver for the injector.
Are there other parts behind that?

I found a "seal kit" while hunting for parts for sale, but it seems to just be a bunch of thick O-rings. Are they the "easy" replacement for those black plastic bits? Are they recommended?

Thx -CTH
PS. I'll post pictures of my home-made from spare Mercedes & VW parts injector cleaning machine once I repackage it a little.