I've seen the shifting lag also, and agree it's annoying. I see it most often when doing a "rolling stop" through an unposted intersection, or those types of situations, rather than in normal cornering.

As far as mileage, I've already noticed my mpg has dropped an easy 10% just due to colder weather (averaging about 33 to 45 degrees lately). Where I was averaging 36 mpg during the summer and early fall, even with A/C, I'm now getting 32-33 with the same driving (and no A/C). This is with a 36 mile commute, one way, almost all highway. My previous Civic Hybrid had about the same percentage mpg reduction in winter driving. So anyone that's noticing an mpg reduction lately, and who lives in an area where the weather is cold.... it's normal.