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Ok, well I did some calculations, and was wondering, how much of a difference will a 5% increase in the total diameter of the wheel and tire make as far as speedometer/odometer accuracy? Also, is it possible to get the speedometer adjusted by the dealer to compensate for the difference? (since I know Honda sells larger wheels)

Here's the numbers for anyone interested:

Stock 15x6 Honda Wheels
Stock 185/65/15 Firestone Tires
185mm X .65 = 120.25mm sidewall
120.25mm X .0394(in/mm) = 4.738" sidewall
4.738" + 15" = 19.738" total diameter

Custom 17x7 Wheels
Custom 215/45/17 Tires
215mm X .45 = 96.75mm sidewall
96.75mm X .0394(in/mm) = 3.812" sidewall
3.812" + 17" = 20.812" total diameter

Even running 205/40/17 tires, the total diameter still increases by 1/2 inch. Oh, and I just realized that the stock numbers would be for the EX, does anyone have tire sizes for the 14" LX wheels?

 
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You need to multiply the sidewalls by 2, there's 2 sides to the tire when you measure diameter. The diameters should be more like 23.8-24, and there's only about a tenth of an inch or so difference between a 215/45/17 and a stock 185/65.

 
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Hes correct. If u look up the stock tire on firestons website it tells u the overall diameter which is pretty close to 23.6 or .8 if i remember correctly. 45's will be much closer to the stock diameter compared to 40's. And i dont thin honda will change the speedometer cus that would requrie tampering with it. But then again its prob just bets to call honda and ask.

 
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I run 205/40/17's and when cruising with everybody down the highway I dont even notice a speed difference. I can trail the person in front of me who's doing 70mph and look at my speedo and it'll say 70mph also. I think of it this way, when your doing 100mph, you really only doing 95mph. If your doing 50mph, your really only doing 47.5mph. It was a big concern of mine at first but now I realize it doesnt matter.

I think to recalibrate the speed you'd have to get the ECU reprogrammed or use some other device that can adjust the ECU programming.