Is it possible to that the speedometer and odometer recalibrated to be accurate ?

I have 18's with 40 seris which is taller than stock which I believe means I have more milage than the odometer shows ?

Here's a tire size calculator (http://www.miata.net/garage/tirecalc.html) to see how much your speedometer is off. No, I don't believe you can have them recalibrated. With taller tires, you will go faster and farther than your instruments show. This could also mean you get slightly better fuel economy (if the wheels/tires are not really heavy) at the expense of acceleration.