its different on paper than actual in a real scenario , think it depends on different factors ie/ the intended use , fuel , goals , etc.
Most people who race or are in the perfomance area generally run twins , petrol or diesel ! twins or multiples are lot more tuneable ,when singles are more...
I have a 89' SWB toyota landcruiser 4x4 , just bought a 13BT ( 3.4 toyota direct turbo diesel engine )as a builder and plan to build and blueprint it ( possibly bore block to take bigger sleeves for more displacement ), will order custom lower compression "Arias" forged pistons for it @ around...