Fuel return line

I usually see fuel pressure issues more often in low wings. I have replaced some Faucet fuel pumps with the next module higher because they do pump another psi or two, but the real reason I do this is because it has a higher rated draft spec. Draft is the distant from the fuel level compared to how high the pump is above the fuel. With the ones I have done this with their low fuel pressures went away. Plus with the higher fuel pressure spec from Rotax for the carbs the extra 1 - 2 psi increase in the newer pump has not been an issue. When making any change make sure you're using a solid scientific  reason to do so and any affects it may produce.