Looking to go back to OEM wheels and tires. Can I expect a huge noticable difference by getting rid of my 22" wheels on 305/40r22 and going to the stock set up of 17" wheels and 70 series tires?

 

Both the forms of the wheels are good and your decision to fit the small one is also good for your car and averagely sensible people used the smaller wheels.I think on 17" wheels the ride quality is better than the higher one.