i know these things aren't accurate at all but at idle my narrowband reads a few bars into the rich side. i hear that too much fuel can wash the motor oil away from the walls internally and cause damages. my car has been running kinda crappy and starts up rough. if i get a FPR and adjust the pressure a bit lower would it be safe to adjust it so at idle my narrowband reads in the middle of stoich? i'm getting a fuel pressure gauge also so i'm going ot check what pressure my stock regulator's pushing out.

 

Most cars run a bit rich from the factory anyway (safer than running lean) so you can usually get away with leaning it out a bit without sacrificing reliability.