I'm not sure about how different it would run with EFI vs. a carb...i don't know if there'd really be a difference?
As for the lope i'm fairly sure it's rougher...but then again every X303 i see a video for sounds like it's gonna roll the car over on its side from all the lope, and mine's nowhere near that rowdy sounding.
Just remember, the right cam doesn't necessarily lope...i love the sound but i also love that i can call it a "mild cam" since it doesn't sound as mean as it is.