I need to know the widest I can go with a stock 14x6 rim. I know 205/60/14 is the largest size that'll fit the front, but can i go wider at the rear?

Don't go too wide. You can probably fit 215, but it would not aid in turning. Try 195. If the tire is too wide, it you have to put a lot of pressure in it or the tire will roll over on it's side wall.

Well, I was told a little while back the rim is not 6" wide but 5.5". That takes care of my decision. There is no way to put a size larger than 205 without excessive tire wear. It'll be 205 at the back and 195 in the front.