I would say no. I looked at the site and it looks like only the premium warranty with bumper to bumper would cover head gasket. I have a 98 Deville with 99k and it would cost me a little over $3000 for the warranty with a $100 deductible. Since a head gasket repair that is done right with timeserts and everything would cost in the neighborhood of $3800-4000, I wouldn't pay for the warranty and just assume the risk on my own. I haven't heard of many tranny problems with the deville and head gaskets aren't usually an issue until you have 100-150k on the engine, and then only if it overheats. I would say save your money and keep your info center on coolant temp and if you ever get to 245 degrees F or more pull over, shut off and let it cool awhile. The computer won't tell you that you are overheated until you get to around 260 degrees F. The thing with headgaskets and an aluminum engine is if the aluminum engine overheats there is a good chance that it is already too late. Keep the temp low and you should "never" have a problem.
By the way, mine normally runs in the 195-210 degree F range. Fans don't even kick on until 222 F unless the A/C is on then they automatically come on.
By the way, mine normally runs in the 195-210 degree F range. Fans don't even kick on until 222 F unless the A/C is on then they automatically come on.