kiimop

So i recently bought, registered and tried (emphasis on tried) to replace my o2 sensors for emission testing. (i drive an 01 Gs300, live in NYC). Everything was smooth sailing until it came time to remove and replace the sensor on Bank 2 sensor 2. IT WAS SEIZED IN. I figured this out after ripping it from my cats by accident. So now i'm in the market to replace it, but at the same time i'm thinking now is a great time to just plain old Replace the other and upgrade them. Nothing to serious though, still want to maintain the luxurious feel to the car. Any suggestions on parts? Manufacturers? Setups?