I found one of those header style exhaust manifolds off of an 86 Aerostar 2.3! I am going to go purchase it this week sometime and run true dual exhaust. I will let you all know how it works out. Now, I am looking for some opinions on what kind of exhaust I should put in my N/A 2.3 to get the deepest most 5.0 like sound out of it. (I know it is never going to sound as good as a 5.0, but you can get it close...ish) Should I use 2.25" or 3" exhaust. Is 3" exhaust going to hurt more than help? Also, what type of mufflers should I look into putting on to give myself a throaty sound? Flowmaster, MagnaFlow? I know this is a lot of questions at once, but any help would be appreciated. Thanks in advance.

You'll be fine with 2.25".
. As stated the 2.25 will be just fine, no need for bigger on a non-turbo motor. Mufflers are upto you, and what you want to pay for how it sounds. I have heard quite a few differnt types on 5.0's, flow masters is the usual dull droney sound, borla is nice, super turbo muffer sounded good ( I forget who has put this on there 2.3...), also flowpath from mac...there are so many differnt versions, basic go by what you like, or whats readily availble too you. Exhuast shops usualy carry flowmaster though. Sounds like an awsome exsperiment, dont forget to post sound clips!
all else fails just go with 2" tubing to 2.5 or 3 inch tips. It is kind of exsperimental, so u take it as it comes, if i wasnt going turbo i would have been already give my best attempt at it!