I am looking for some larger injectors for my Miata.

I am currently running the 19550-2010 460cc injectors from a non-turbo. I would like either the 19550-2020 550cc ones from a TII or something a little larger.

Does anyone have a set of the 550s for sale? Or could someone tell me what they upgrade to from the 550s if I want to go the next step.

Thanks in advance.