I received a notice from Honda regarding our 2005 Honda Civic Hybrid with CVT. The notice states that ECM firmware needs to be updated at no cost to solve DTC P1420 and P2000 error code detection thresholds, as well as extend the warranty on the oxygen sensors to 80,000 miles. Here's my question: Somewhere else on the internet, credibility unknown, I read that one of the hybrid ECM updates resulted in a reduction of 10mpg or more in the vehicle's performance. So far we have not had "Check Engine" lights, so I'm a bit disinclined to get the update installed at this time. Have you heard anything, one way or the other, on this update? The letter is dated September 2011, titled "Product Update: ECM Update to Improve DTC P1420 and P2000 Detection Threshold". Thank you.