The wife and I have racked up more than 500k miles on 9th & 10th gen Bonnevilles and never once had a warped rotor.
Also I do not drive gently
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Every time I have had front end brake shimmy, it has been due to sticking caliper mounting guide pins.
On the 92-99 style, corrosion outside of the rubber boots causes them to squeeze down on the metal sleeves on the guide pin bolts.
On the 00-05 style, the rubber guide bushings in caliper anchor bracket get gummed up - most likely from contaminated or deteriorating caliper grease.
With caliper installed and pads removed, you should be able to slide the caliper in and out evenly by hand, without a lot of resistance.
If not then you need to remove and clean or replace the guide bushings.
Other '00+ guide pin problem I have seen:
Sometimes when you slide the caliper in, it can have a spongy feel or even spring back out on its own.
I think this is caused by an air pocket being formed at the end of the pin.
The guide bushing has slots that run lengthwise on its outer surface. If excessive grease has accumulated, air can not be vented through these slots nor along the shank of the pin.
This has been my experience - hope it helps.
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Also in regard to the comment about trying Brembo - that was my thinking years ago but I found that for OE parts they just cash in on their name.
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