I am on the verge of buying a TSX with the following options, but I have a few concerns because of what I want...

Indigo Blue Pearl 5AT
18" TL rims and 235/40/18 tires (Toyo Proxes T1-s or Yokohama AVS ES100, may go cheaper depending on total cost of car)
OEM Kit: Front Skirt, Side Skirts, Rear Skirt and Rear Spoiler
Door Edge Guards
3m protection for front bumper and hood
7 year warranty

Concerns:
Will putting 18" rims and 235/40 tires affect handling and ride quality?
Am I going to be needing to replace these tires every couple of years?
Do I need to lower the car because of the size of the rims and how will lowering it affect handling and ride quality?

This will be my everyday car...to go to work...to get groceries...to drive family around. I live in Toronto, Canada so I will also be putting on 16" steel rims with winter tires. I don't want to have to trick the car. I just want the look of the rims and tires. Any help is much appreciated.