Thank you, Guys (and Gals?), for all of the helpful advice. I am in Portland, so we are talking rain, and rain, and rain.
(It grows on you.)
"I was never able to get the rear of the car loose..." NJGuy, quit bragging! I'm so jealous!
I just got new rear shocks, front struts supposedly fine. The front rotors are warped, but will be fixed with new pads later. Don't think this would contribute, though it is causing some shuddering when I decelerate from high speed.
On one hand I'm glad this problem is not common to this car generally. Reassuring. Yet on the hand it means my car is handicapped. I will definitely look into tires, and invest as soon as I can. It would be great if that is the problem, as most people are suggesting, and the tire people deny. That would be an easy fix.
And XIS, maybe your RWD EX35 could smoke my C30, but mine sure can't. Wah!
Anyway, thanks everybody!