need some fuel delivery advice for my DD
 

i see race applications on here, and aftermarket regulator threads, but nothing about in-tank or in-line aftermarket replacements. i like the idea of an in-line pump. msd makes one for 120 bucks but it says max 40psi. is that enough for a 13b from an 87 fc? i remember reading the required pressure was around 35. that seems to be cutting it close. i have a walbro 255 in tank that just crapped out on me. also, wiring. should i bypass that resistor setup so it's at one constant pressure? if i go in-line, how do i adapt the tank, do i need a sock in there, can i just modify the stock sending assembly? what's the best way to go about this? would prefer in-line but i'll get another wb255 if i gotta. i'm new!

Need some info about the car. Turbo or non-turbo? Upgrades?

There are plenty of options for stock style drop-in pumps. There is no reason to go through the hassle of converting to an inline pump on a non-racecar.

NA's will be good with a stock replacement pump. If it's turbo, it will depend on upgrades.

i would say a stock pump

I would agree except the Mazda OEM fuel pump is over $300, twice the price of a Walbro or any number of aftermarket pumps.

look how long it lasts, heck he can probably get a used one and it might outlast them
even a stock bosch replacement @ about $80-100 or so

I'm at 5 years on a used FD pump that I picked up for $30. It's easy to find stock pumps that people remove to upgrade to something larger.

Since OP mentioned a resistor/relay setup in an S4, it has to be a turbo. So the pump chosen must be able to support his needs. I'm partial to Denso pumps, so my suggestion would be FD, Cosmo 13b, Cosmo 20b or SupraTT depending on the fuel needs. I have no love for whinebros.

Without the OP mentioning the car type,etc,you have to guess. (The car in his profile is 87 GXL)
Please put this in on future Tech questions as it really helps speed up responses.