I agree with Joe. I've driven a few different 300Cs with 22's, as well as also being a passenger in these same cars, and the ride quality was 'miserable', as compared to the stock '300 series' tires/wheels. This is due to the nearly non-existent sidewalls of the low-profile tires which have to be utilized with these over-sized wheels. Like Joe said, this allows one to experience every little bump and crack in the road. Before you actually purchase a set of 22" tires/wheels, first borrow/test drive a similar vehicle (equipped with similar tires/wheels) and then drive across a set of railroad tracks and/or through a mall's back parking lot...definitely not a pleasant experience. 
My '300 Touring' came originally equipped with 17" tires/wheels and the ride quality was smooth. I upgraded to 18" '300C' tires/wheels (with non self-sealing Conti's) and the ride quality didn't change all that much...it was still smooth. I then had the opportunity to drive a '300C' with forged aluminum 20" wheels with hi-performance tires, and I must admit that the handling had substantially improved while the ride quality was still relatively smooth and by far acceptable. I'd really hate to hear later on that you had in fact decided to invest so much money for tires/wheels that your wife did not appreciate. Also remember, that used tires/wheels will be worth about half as much as what you originally paid for them, if even that much...just read our 'Buy/Sell' section, as well as scan some eBay listings.
Personally, I too like the look of some of the 22" tires and wheels (as I've always felt that the stock tires/wheels simply look too small on our cars), but after reading through numerous threads/posts by those who are/have experienced 'ride quality' issues related to their recently purchased 22" tires/wheels, I therefore decided to upgrade (once again), and purchased a set of 'SRT-8' 20x9 forged aluminum wheels with Goodyear 'F1 Supercar' tires.
My '300 Touring' came originally equipped with 17" tires/wheels and the ride quality was smooth. I upgraded to 18" '300C' tires/wheels (with non self-sealing Conti's) and the ride quality didn't change all that much...it was still smooth. I then had the opportunity to drive a '300C' with forged aluminum 20" wheels with hi-performance tires, and I must admit that the handling had substantially improved while the ride quality was still relatively smooth and by far acceptable. I'd really hate to hear later on that you had in fact decided to invest so much money for tires/wheels that your wife did not appreciate. Also remember, that used tires/wheels will be worth about half as much as what you originally paid for them, if even that much...just read our 'Buy/Sell' section, as well as scan some eBay listings.
Personally, I too like the look of some of the 22" tires and wheels (as I've always felt that the stock tires/wheels simply look too small on our cars), but after reading through numerous threads/posts by those who are/have experienced 'ride quality' issues related to their recently purchased 22" tires/wheels, I therefore decided to upgrade (once again), and purchased a set of 'SRT-8' 20x9 forged aluminum wheels with Goodyear 'F1 Supercar' tires.
