I plan on keeping the factory EFI that comes with the LS motor. The main decision I'm trying to make is getting the fuel to the motor. Seems like the easiest route is to pick up a cheap 12-16 gallon fuel cell on CL, drop the factory tank, add an inline 340-380lph pump(aem or summit), filter, regulator for a couple hundred dollars and then plum the return to the fuel cell since most already come equipped with a vent and return fitting. Or just go with the package deal from Tanks inc for about $500 or so shipped and just replacing the factory tank so it keeps it all stock looking, and replace the factory tank with their FI tank setup.