I've got a new set of 44lb injectors but am considering selling them and picking up a set of 60lb injectors instead. My question is, what should be done to a set of used injectors to ensure that they are flowing correctly/ ready to install? Should they be sent off and cleaned, or is that something I could do myself? Should they be flow matched, or is that necessary? I'm just worried about picking up a used set and then having fueling/tuning issues from them. Any recommendations are appreciated

 

Send them off and get them cleaned. They will tell you if they are mismatched. Flow matching is accomplished by buying a new injector to replace the oddball, and then you put the oddball into a garbage can.
I had one injector that flow a lot more, it makes for fun idle tuning.