Which screen should I purchase when replacing?

Im trying to replace the cracked screen on the EVO 4G. I've already seen the instructions to taking apart, I take apart iPhones 3G and 4's so it doesn't look very difficult specially since im use to heat gunning when doing ipod 4th gens. The thing is I heard theres different screens you can purchase, such as a smaller ribbon and wider. Is there anything in particular I should be looking for when ordering? And if so is there any way I can tell without opening the phone? Thanks for any replies.