for every greddy kit it comes with a blue round fuel regulator(the one that's able to sense the boost in order to increase fuel deliver). if i use this thing, do i still need my aem fuel regulator? cuz i heard that if i set the aem to 47psi something and when the blue one senses big boost and tries to deliver more fuel(like 57psi), the aem wont let it pass cuz it will only deliver what i've set----47psi. so is it better for me to get rid of the aem and just use the stock fuel pressure regulator?

but how do i set it? what psi should i set for the aem? since i dont have a air-fuel gauge yet, so i dont know when it's lean and when it's rich.

please help!

take off the aem.

the best thing would to sell both of them and buy some 450cc injectors and an Apex'i AFC

You can use both. The AEM will set your "baseline" fuel pressure. The FMU that came with your kit will restrict the return line to the tank when it sees boost and that will build pressue in the fuel rail and injecters. Set the AEM to the stock setting and let the FMU give it more fuel under boost.

i used to get 30mpg without the turbo. after the turbo(but without aem fpr)i was only getting 27mpg(and that should be normal). but ever since i put on the aem fpr(47psi) i started getting 30mpg again, which means the engine is not consuming enough gas even when it's boosting! what should i do?!!

as siko stated, you use the regulator in conjunction with the riser. Set your base pressure with the aem regulator, and then the riser will multiply fuel pressure according to boost, depending on what rise rate you have. I wasnt aware that greddy kits came with risers, i thought they just had the blue box or whatever with some injectors and a fuel pump. the 'blue regulator' you describe sounds like a vortech riser.