I am running hahns kit with a sfmu right now and was wondering if I install a walbro 255 can I get rid of the anoying inline pump? Also Im going to be running accel #40 injectors and besides changing out the spring and disc in the sfmu do I need to adjust the screw or will it just adjust itself with the higher vacume when I turn the boost up.

yes you can run a walbro instead of running a in line pump . i lot of people just use the walbro .

the fuel pressure will adjust itself cause your changinng the disks but you still need a FP gauge to see what it's doing imo. you should have to set your static and idle FP again.

Just run the Walbro.

If I install a walbro 255 with my inline will it be just as quiet as if I only had a walbro? Also will I get worse gas mileage if I have both installed?

Dude, the return line dumps axxess fuel at idle and shit. If you keep your foot of the mat you won't use as much fuel. :P