I would also avoid a B-series swap as they are heavier by enough to effect the handling of an EF hatch in a negative way. It's the same reason that it's not recommended to put an H-series swap into an EG hatch. I suppose if all you want is speed in a straight line, then go for it... but part of the appeal of Honda Civics (for me) is how well they handle on twisty roads. You want a light quick car with good weight distribution for the most driving pleasure imo.