Are any of you folks who are going to extended OCIs worried about warranty issues? Myself, I just can't see the point in an extended OCI until the powertrain warranty is done.
I read on another board about a guy who'd extended the intervals and ended up with a sludged/trashed engine at about 24k miles. The problem turned out to be coolant in the oil. Toyota denied warranty coverage because of the extended OCI. The synthetic oil mfr. denied coverage because it wasn't an oil problem.
Seems that the extended OCI doesn't save that much money or trouble to compensate for the risk, even if it's small.
Toyota, BTW, specifically says that synthetic is fine but you must follow the normal intervals. If you do lots of short trips around town in cold weather that would count as severe service and the OCI would be no greater than 5k miles.
On the subject of the over-tightened filters, I suspect that's not a matter of the initial torque on the filter. It's probably that the first filter sealing ring seats on a new, clean, oil-free surface and it bonds really well. It shouldn't be a problem after that, but you should always make to sure to check the seating surface after removing the filter to make sure that the ring came off with the filter.