Mercedes m110 injector replacement

Replacing the injectors on an m110 w123 mercedes 280te. This particular wagen is a donor (interior) car but I wanted to try a few mechanical tasks id not done before as a hobbyist (non mechanic). The car was very lumpy to the point of stalling if not revved until warm, and very smokey! I had the air filter housing off when I recorded engine noise and the manifold is very noisy so you cant fully appreciate the car putting along. I only changed the injectors, ideally you would do the sleeve under them which I understand is quite simple. The car now starts a lot easier and runs better without the need for much rpm's. I changed the spark plugs at the same time which also I think helped as they were also completely caked in buildup! Constructive feedback can be left in the comments. Again, not a mechanic so dont take all I say as fact - but the task was not too complicated I feel.