@Rockhead,
And Subaru--The Motorrad has done pretty well with the Boxer.
BTW--V4's do pretty well if they fire as two's, becoming, essentially, a V2+2.
And the V-twin configuration makes a great light engine. It's limited though, and has only been used on motorcycles, stationaries, motorcycles, lawnmowers, and ultralight aircraft.
Also boxer and V twins really shine as air cooled engines-- boxer 4's less so.
Rap