RE: 90 Degree opposition crankshafts...
Yes, they do twist / lift the bike's chassis a bit. It varies by design. Having had both Boxer and K-Brick engined bikes (both having crankshafts rotating perpendicular to the rotation of the wheels), neither design is "startling" in this respect, even with violent applications of clutch & throttle. Yes, its there. Will you notice it after more than 30 minutes riding the bike? No.