Hi can someone tell me how big of a rim and tire i can go with on a stock 240? I was thinking of going with either a 16" or a 17" want to get a low profile but also fill the wheel well . any ideas?

This has been addressed so many times it's not funny. Take a look through the Tire/Wheel section. Or do a quick search. Or find a good local tire/wheel shop with knowledgeable people and ask them to help you.

With a lower profile tire you'd obviously be able to go even bigger than this on the rims although actually finding such tires would be a problem:

Make sure your wheel/tire combo is around a 25" diameter and you should be fine. You'll need to be careful how "fat" (wide) your wheel/tire combo is however, as you don't want fender rubbing.