If you live in the North and have a 2000-2005 Bonneville, you may want to check, clean, and proactively maintain the unibody at the exact point about where the rear springs meet the unibody. I was inspecting the rear shocks and noticed a bunch of crud sitting there. I cleaned off the crud and noticed the unibody had corroded through at this point, hidden by the crud. I suspect a typical GM issue- they have points where water and salt can collect but no where to exit. The salt sits there and eats away- no car wash is going to remove this salt.

This is a place to target for regular cleaning, inspection, and protection during and after a winter in the north. I my case, I will be looking to treat with rust retarder- but the situation on my Bonneville is not good.

I wish I would of known of this years ago- easy to address- just remove rear wheel and clean, and it might not be in the shape it is in.