The stock tire size on my car is 205-60-16. I want sporty tires that have a better speed rating than v. To perfectly match the stock tire size of 25-60-16 would be 245-45-17 (tires bigger than 17's the price skyrockets) Would a 245 series fit my 00 accord v6 coupe?

 

205-60-16s are 8.07 inches wide by 25.68 inches tall.
245-45-17s are 9.64 inches wide by 25.68 inches tall.

to figure this out, have someone cut and hold the steering wheel all the way in each direction, and measure the distance from the tire to the inner fender lining. check it at the front and rear of each tire and that way you will know if that added 1.57 inches of width will make a difference.

 

I would check out this web site for tire size calculator. It's really helpful.
http://www.miata.net/garage/tirecalc.html

 

This deserves a bump. Very useful. I didn't realize that a shorter sidewall on a larger rim actually results in a total diameter that is almost identical. IE: 215/45-17 -> 195/60-15 is the same diameter. I'm so used to 4x4 thinking where smaller actually means smaller. :-) This metric stuff is a PITA! Just tell me how big the frickin' tire is! You know?

edit: Here's another calculator: http://www.1010tires.com/tiresizecalculator.asp

 

Here's another tire size calculator: http://www.1010tires.com/TireSizeCalculator.asp