Fuel Cell and sending unit?

Hey guys, im ordering my fuel cell for my notch, the only thing im not sure of is what OHM sending unit to use. SOme of them say GM 0-90 ohm, and some are like 70 OHM or something. I would assume that no matter which sending unit you get, you need a fuel guage to match it. I might go with an aftermarket fuel guage, so then i dont think it matters what i go with as long as the guage matches the sending unit right?? If i stay with the stock guage, what sending unit would i need????? thanks guys, this is the first time i hooked up a fuel cell so im not sure what to get.