Pazzer

Hi everyone great forum here - a lot more active than the Aussie one. Hopefully being a Pom you will tolerate me! I'm considering buying a 430 or a 450h. For my budget I'm looking at 2005/6 models. Here in Australia the hybrids come at a premium - typically 20% more than the V8. So the trade off for me is the efficiency vs the upfront cost. I intend to keep the car for at least 4 years. One key concern is the life of the batteries on the hybrid. Anything I look at will be out of warranty and I'm nervous about a battery fail and associated cost. What kind of life should the battery pack be good for? Appreciate your responses.