How to get more money/credits in Gran Turismo 4 Spec II

Sup ya'll! I am so sorry if someone the things i said were misleading (such as the selling price for the RSC itself, my bad.) I was pretty nervous recording the whole thing tbh. But really, i appreciate it if this helps anyone playing the Spec II Mod of Gran Turismo 4. Also i would appreciate if you share this to people and click that sub button! See ya later. no socials yet :(