Bilstein is a nice upgrade. Part number: BIL 24-107440 from these guys: AJUSA.com. cheapest vendor I found online. Took a couple of weeks to get them but if you're not in a hurry . . . .

I have the sports suspension on my 4.4 and these are definitely an upgrade. the part number I listed above is actually for the 4.4 with sports suspension. most vendors have the description listed incorrectly as not for the rear self-leveling - sports suspension.