What size tires can i fit on stock prelude rims?
 

its a 1994 Honda Prelude Si Stock rims, they are 15 inches and right now I have 205/55/R15's on them i want to go wider, whats the widest i can go on those rims?

If you "go wider" the diameter of the tires will change too, so you'll be not able to reach the max speed and the performances od the car will decrease.So keep the original size, or change the rims.