bad idea
I just did a cc503 swap with all bolt ons, and I have a 125 wet kit installed. I havent sprayed it yet with the cam. Is it a bad idea to spray with a stock fuel pump? it has 40 psi at idle. I dont have a fpss, but I could get one. All I have is a window, WOT switch.
With a wet kit fuel pumps as well as injectors are not as mandatory like as in a dry kit. Im not a nitrous expert but I would assume you to be fine but I would personally feel more at ease with a larger pump just in case.

