twins for the street and single for drag racing.
twins spool faster because there is less rotational mass and twins can be closer to the manifolds. Exhaust turbines use both velocity of spent gasses as well as heat energy to spin the turbine.
Singles have a much bigger mass to rotate. but once you get them spinning............Look Out.
I'm an A&P mechanic and I currently build the worlds most powerful turbine. The GE90-115B.
The next time you go to an airport. go find a small regional Jet and notice how long it takes to start the engine.
Then go find a 747 and see how long it take for it to start.
I think it will give you a good perspective.