...in the specific packaging of each engine. With today's turbo technology and trying to make bigger power numbers, the ease of installing a large single can give an I6 an advantage over a V6 when comparing the Supra with the Z specifically. Also, a big single does not automatically makes a car a dyno queen, thanks to the newer GT series Garrett technology and split scroll turbine housings, etc. As it always has, the answer for what you need lies in the careful research and planning of each specific setup. It is never a simple answer like X>Y.