Has anyone else had an issue with the driver's seat clicking/clunking during acceleration. One can also feel the clunk/click through the seat as well. I have the momentum seats. Brought it into the dealer and there is some flex in the seat which they think say designed to be that way and did not offer a fix. This sensation/sound goes beyond just the normal flex designed into the seat and the WHIPS system. It does not feel correct and was not something the car did when originally purchased. It almost feels like the seat is loose on the tracks , but it is not shifting as far as I can tell. Any thoughts on what it could be? Anyone else with a similar problem?