I hope I'm not being referenced; I don't believe in magic. I do think my Sachs rides quite nicely, and I think the lower bb is part of it. I've found that I consistently prefer lower bbs. I do feel a notable difference in frames and am a lot heavier than you...I didn't care much when I was younger and thinner. I could definitely tell frames apart at high speed; some are a lot more stable. I do think how bikes are built can influence ride...not as much tires though. My Sachs isn't my favorite riding bike, but I do like it.

I also think that bikes we think are faster often are...it might be psychology, but I also think it has some truth to it.