Buying parts new for a car this old is pretty silly.
Piece the windstar kit together IMO. Call the guy up and see if he'll sell you the angled TB spacer and the rest of the kit for a reduced price, then go get the intake yourself and save a bunch of money.
Buy the pulleys used. Its not like pullies go bad.
http://www.moddedmustangs.com
http://www.3.8mustang.com
http://www.mustangcollective.com
http://www.v6power.net
Hell, get on Craigslist both locally and an hour or two away. If you can save $50-$100 on the part buying it on c-list it's probably worth driving 2 hours to get it.
I was talking to my 3.8 friend and he said not to get the TB. He put it this way, "The stock one flows plenty, those are for boosted applications primarily." Companies put up testimonials that sell product. That's why you see such wonderful things being said about the TB in the testimonial, but everyone who's not affiliated with the sale says don't buy it.
Idk what the alumium driveshaft situation for your car is like but I'd get one if you can get one for cheap. Those reduce rotational mass by a lot (frees up horsepower and torque) and are much stronger and more stable than the stock one.