I e-mailed Wolverine about their oil pan heaters, and here's the response I got: "Ben, Your car will use a #9. The heater will heat oil at approx. 1 degree per minute. It's recommended to leave plugged in all night so as to get the thermal heating of the entire crankcase area (ie. crank rods, main bearings, cam surfaces and lifters). Approx. heating time of 5 - 6 hours - crankcase temp. estimate of 100 degrees. Our heaters are 15 watts per square inch of surface area. Oil damage occurs at 22 watts P.S.I. and 280 degrees. Call me at 800-545-2248 with any questions. Thanks, Kevin Frank" I was quite pleased with the quick response, & especially pleased with the specific info about 1°/hr and the oil damage numbers. I'm just posting this for reference, and to elicit any thoughts anyone may have on this info. Do these numbers sound reasonable?