If you think of it like trying to suck a thick milk shake through a coffee straw and how much wasted energy you would be spending to try and achieve the same results you would get with a larger straw. Basically the turbos and thus the engine can be more efficient with less effort. Its not all about getting as much boost as you can get its about making the boost you have as efficient as possible.
Hope that makes sense.
" I told my son, you have to catch the football other wise this just looks like child abuse." - My brother
