3.8 V8 351 W conversion

I have a manual 5 speed 6 cylinder 97' pony, all stock at the moment. It was a gift car from my best friend, who sold it to me for 2500, even when other people were offering him 3500, so it has a great deal of sentimental value to me. The engine is starting to go down hill, and with 125,000 miles on it, I think I'm ready to put something worthy of the name "Mustang" in it. (i.e. v8) I've been looking around for a decent priced 4.6, but I'm not liking the price as much as I am the Windsor engines. Is it possible to fit a Windsor engine in my car with any effectiveness, or should I stick with the 4.6 plan? I really don't want to deal with the computer and alternator of a 4.6, will a Windsor bolt in easy, or will it take a great deal of fabrication to make my pony run with a Windsor underneath the hood? Any suggestions are greatly appreciated, however the "trade it in for a GT" theory is out of the window for me. Like I said, this car means a great deal to me. I'll take my time if I need to, save my money.

Thanks for the reply.

15K? That dosn't sound too bad, as long as I take it slow and don't spend all I've got at once. I was thinking of buying a longblock off ebay, ready to drop in and then work from there. If I don't use fuel injection and I stick to a carb, do you think I could possibly reduce price for a short term solution. I want to be able to drive the car in between my moments of upgrading, but maybe that's just too much to expect. That's the biggest reason I'm asking here I suppose ;P

Pateince is going to be my middle name when it comes to this car, I think I'll live with a 3.8 for a while and invest first in brakes, then in suspension, then in the base engine, then in the performance of the engine. Does that sound like a reasonable manner of approching the task? For now I think I'll keep it simple and go with a carb, but I'll definatly keep the Ranger ECU in mind for my future plans. What year of Ranger should I use, or does it matter? And of course, as always thank you very much for your responce.