I know around my way its not so much who is cheapest as it is who has the best service. I know that every major shop within 20 miles of mine price matches the competition. find a place with a good reputation and see what kind of deals they offer for tires.

the tires you choose is completely based on what you intend to do with your VX and what you expect from them. the VX tires sizing allows for many AT tires as well as many high performance street tires.

the oil filter is insanely common. its found on older hondas (94 accord comes to mind) so you can find that anywhere. the Mobil1 number is m1-104. the Purolator number is 14459. I've found that many of the parts are easy to come by, Moog has a whole line of suspension parts, Wagner has a whole line of brake parts. All of them are common enough that I've convinced my shop manager to allow me to keep them on hand, just in case