I would use Valvoline Maxlife Sybthetic Blend if it were my car, it's just a personal choice, but I think Maxlife's additive package is superior to Castrol's and you get some better base oil stocks with the blend.
The FL2005 says its been discontinued in the Motorcraft online catalog and to use the FL400S the "S" means it has a silicone anti-drain-back valve which reduces the startup noise.
How many miles are on the Car and how do you use it? Daily commute with a lot of highway or lots of (or infrequent) short trips around town with minimal highway use?
If you drive alot of highway in a Daily use car I would just use the cheapest oil and filter I could find (like the oil change specials at autozone and CSK stores for 9.99) and just change it every 4K miles. As far as picking a weight for summer I'd use the 5 or 10w30 and for winter I'd use the 5w20. If you want to maximize oil drain intervals and maybe get better mileage get the thinnest full synthetic oil you can afford (like Mobil 1 0w20) and a Mobil 1/K&N/Pure One oil filter.
Old ride: '96 GL MTX Zetec **sold after ten years of ultra-relible service.**
Newest Ride: 2003 Jaguar S-type R = Superchraged Luxo-rocket
--I don't want to hurt you, but it's still on my to do list.--