You can use a single-plane manifold with EFI and it will not suffer the same low-speed power loss as with a carburetor because it doesn't have to transport the atomized fuel all the way from the plenum and you don't get fuel distribution problems from adjacent cylinders pulling in intake charge right after one another and trying to keep the air velocity going (thus keeping the fuel suspended) in that bigger plenum. All production EFI engines use "single-plane" intakes even the V8s, look at the old Magnum manifold or the modern Hemi intake, they're basically laid-over long ram-tuned runners all feeding from one gigantic plenum.
The only reason dual-plane intakes exist is to make carburetors more efficient on cross-plane (Detroit) V8s. They just cause air restriction on EFI setups with no real benefit.