[Redlinez]

My mother in law listened to her Mazda service advisor instead of me (22 years exp as a service advisor) about tires on her Mazda6. She recommended to her to put Yokohama Advan Sports on it for a little less money. I advised her to stick with the Bridgestones that came on it since they lasted 40k miles and she loved how it drove. Or go with the Michelin Pilot Sport AS3. She put the Yokos on then drove to my work demanding I drive it a few days later. You know why. She traded the car for a new Mazda6 a few months later.
I would have to say you going wider also made the sidewall taller unless you went a series shorter. That in conjunction with that tire's performance level caused your sidewall to deflect even more.
I tell my customers at work who are actually in tune with their vehicles to stick with what came on it or I will recommend what I know to be a "better" tire. I always say if you liked/loved how it drove before, buying a different tire could change that feeling dramatically.