Wasn't this already posted on here. Not the article you posted Milo, but the Sakermotorsports website.
compared to other engines (like I4's) boxers are relatively tough to pull power from. That's part of why there are 700whp civics on 2.2L or whatever they are now and people get super excited about a 500+whp 2.5L boxer. But despite being hard to pull power from, boxers have lots of other advantages like small size, small cams and shafts for better power transfer, low mounting for low cg, and oh yeah, that boxer growl :ddirty: