Firstly I would like to say, there is no such thing as a "Best" tyre and wheel sizes for handling. As Smokey mentioned, there are too many variables for there to be a BEST combination. However, what you should be asking is, the most optimal tyre and wheel size to improve handling. I would say this is between a set of 18s and 19s. Tire sizes and prices vary slightly between 18s and 19s and more for 20s. I have found anything from a 225 to 245 for the fronts and 245 to 275 for the rears comfortably improve body roll compared to factory specs.
Next thing you got to figure out is do you have heavy 18s or lighweight 19s? Unsprung weight affects this as well. Then you will need to determine your suspension and ride height...stock or lowered?
If you are not after record breaking times around the track then I would suggest a decent brand tire + lightweight JDM rims + slightly lowered + sway bars. These mods alone will give you a pretty noticeable improvement over factory.