From what others are saying, the hybrid components (to include the batteries) are the same no matter if the car was sold in California or anywhere else in the country. But, California has a 10yr/150K miles warranty, whereas the rest of the country has an 8yr/80K mile warranty. (someone might want to check my numbers, I'm just doing this from memory) So in that sense, if Honda put a 10yr/150K mile warranty on the hybrid parts, the vehicle SHOULD be able to last AT LEAST that long. I'm sure hoping so. I really do plan on putting at least 200K on my car. It would be nice if I never needed a battery replacement, but do understand that I might.
You want to increase performance and increase economy? Usually, they're inversely proportional. At least, in most cases.
At 35-37 MPG, your fuel economy is pretty good as it is now. However, you've already answered part of your own question. Slowing down will net you more MPG. Since you're sticking to 65
MPH, you're pretty much maxing the MPG you'll get, speedwise. The next step would be to be smoother on the accelerations and anticipate braking. You don't have to be abnormally slow when accelerating up to speed, but rather just make smooth and slow throttle advancements up to your desired speed. And for anticipating stops, if you see a slowdown up ahead or a stoplight, start slowing down early in hopes that the slowdown will speed back up or the stoplight will turn green so you don't have to come to a complete stop. That'll help you with a few more MPGs.
There are other tips in these threads. Just start reading and try what you want and develop your own style. You'll find things that'll work for you and get you what you want.