I want to put all season tires on the stock OEM 18" wheels..

I plan to go with the TOYO Proxie 4s. The problem is, the stock size is 225/45-18 and 245/45-18.. These TOYOs only come in 225/40-18 and 245/40-18 (and 235/40) Is this a problem if I were to go with that setup with the 40 instead of 45.

I really don't know much about tires, so I want to know if this will work or not. Besides speedometer differences, will there be a fitment problem, or an allignment or handling problem or something? I want to order these now, so excuse me asking on this forum, but this is the quickest forum.

Thanks!