I feel the idle is already getting quieter. Yesterday when I got home from work the hot idle was almost back to normal, though fast and cold idle are still loud, and in my experience with other fuel-related work like delivery valves, are the last to quiet down. There might be a slight performance improvement with these nozzles on second thought, but it's not huge by any means and it's not supposed to be. I'm just not very good at telling minor differences in acceleration. I'm much better at analyzing engine sound.
I hope my posts in this thread are interesting or useful to someone here and I'm not just posting my own diary here.
