Don't wait for the 105K timing belt change to use good engine oil. This is not a cast iron block that relies on oil splash technology, it has oil nozzles that spray up into the cylinder walls for complete lubrication. At 80K, I doubt that any seals are so completely coated with sludge that the seals dried out. Go ahead and make the switch, the engine will love it. Especially if it is lugged around town all of the time.
Check the manual for viscosity.
Dealers use "blend"s because it is cheaper, not better. They will love it when a car comes in with a clogged oil separator; first, the replace the leaking seals, then a few months later they charge you again for replacing the oil spearator because the seals are leaking again.
--
My name is Klaus and I am a V ♂ lv ♂ holic.