with twin turbo, you have to buy 2 turbos, run more piping, etc. waay more of a pain in the ass. the only advantage is that you can use 2 smaller turbos instead of one big one. this eliminates lag, but just barely. one big turbo is the way to go imo. sissies always complain about a few hundred rpm of lag, buy turbos that are too small, etc. give up a tiny slice of bottom end power for a shitload of top end.