The stickys at the top of the page are your friend
Chart of maximum tire size
To answer your other question, you'll definitely want to regear if you combine 33s with the 2.3L. It's most likely going to be sluggish either way. I regeared with a 3.0L and it still isn't great. Good thing I'm switching to a 5.0 soon.
Search around for others with your engine and that size tire to see what they did. There's a wealth of information on this site, you just have to look for it.