ok first things first... the fastest cars in the world use superchargers, plain and simple, but these are also blowers that are so fucking big it takes over 1kbhp to just turn them, they make upwards of 6kwhp at the very least.
second, i have NEVER understood what the big deal about boost from practically idle was, do you race at under 3 grand??? if you do, you shouldnt own a vehicle. honda engines make their power up top, so obviously, that's where you are going to want that thing stuffed full of air, not down low, up top superchargers run out of breath, unless you're running a massive blower, and if you are, you prolly dont have a civic. lol... anyhow
the most efficient cylinder engine is a flat engine, or horizontally opposed if you like. this explains the design of f1 engines and why there are rules against the engine actually being completely flat. not only is it more efficient, it also lowers the center of gravity, which is a good thing.
also, whoever said that auto-x guys go for big single turbos, you're on crack. in auto-x a big single turbo would actually be working AGAINST you, you want it to spool as fast as possible.
i say ditch the twin turbo civic, unless its a twin turbo nsx engine, then that's a totally different subject
anyhow, if you're going to drag, i say single turbo, none of that twin stuff, if you plan to auto-x, go with a roots style blower.