I did this 2 years ago. I also live in California. Quite frankly, I wish I had kept the Polaris 280 and just had shorter run times on it until it really broke. I think I would have gotten more value for my money that way. That being said, I would first recommend looking into The Pool Cleaner - pressure side. Others have had good results with that. The plumbing modifications would probably be much smaller with that change. They would basically replace your booster with a valve is my understanding.
I switched to The Pool Cleaner for the suction side. I like it okay, but I just wish I had let the Polaris live out its "life." It took much less time to get the pool clean. The Pool Cleaner easily takes 4 hours. If I want to have a morning party, I have to turn on the pool earlier to get it clean looking or manually vacuum it, which I never had to do before. The suction side cleaner also takes some of the suction away from the skimmer. Since I went to a smaller variable speed pump, that had some effect too, but the surface of the pool just isn't as clean. Also, my steps now need to be manually cleaned as well as the water line. I like things easy.
Try running the Polaris every other day for only a couple of hours and see what happens to your bill. That is my honest opinion.