I believe the EF/EL XRs have a larger fuel pump? (I'm not sure if it's the fuel pump and thus the reason for this thread) that rasies the fuel pressure when compared to that standard variety.

What is it that actually does this? Is it a larger fuel pump?

Same fuel pump.

Different fuel regulator.

300kpa fuel regulator as opposed to the 270kpa stocko (sits on the end of fuel rail)

Link below is a mod posted how to achieve same pressure without buying one..... do so at your own risk i guess
http://www.fordmods.com/forums/fuel-reg ... 70177.html

Or you can buy a Bosch item..... part number 0 280 160 548

I dont know the effects, or performance increase if any? Only if your car was leaning out, then would be a wise investment

i dont know if that mod will be as effective with ef's >> as the reg is a lot more compact.