External BB bearings and aerodynamics?

Does having your BB bearings hanging out (a la new integrated cranks) make your frame less aero by any significant amount? I can imagine that they are stiffer but I also seem to remember something about super narrow BBs a couple years back. I think Lothar Leder had a frame with a narrow bb for Hawaii…perhaps his CUBE frame?

Just curious about the tradeoffs. I’m sure it’s all in the noise!

Walser frames favored by some pro road racers (most notably Jan Ulrich) are noted for narrower (not super narrow) bottom brackets but how much advantage are they going to generate when they are constantly awash in the turbulent wake that is generated by the constant repetition of the descending crank arm/shoe/leg?