I'm still torn between new BC and used AWR. New BC I can get the spring rates I want out of the box, the AWR used I would be buying new springs for all four corners (extra $240 plus shipping). I don't know, maybe I could buy the used AWRs, use them for a season with the springs they come with (10" 275F, 10" 325R) and get new springs for 2010. Rogue really liked the BC when compared to Tein and K-Sport, so it might be a nice starting platform for me.
When you are referring to used AWR's you aren't really specifying what you are getting... The one's that will come with the Koni's or the Bilsteins?
As Britt stated, different valvings are going to cost more with the Bilsteins, so if the AWR's did come with Koni, I would strongly recommend that.
In regards to new springs, you can go on the sccaforums and find used springs for fairly cheap.
Like I stated earlier, the ideal setup would be to use 7" all the way around.
Front Setup
8" Spring will get your spring perch all the way down to the bottom by the sway bar mount, so you can't lower the car anymore.
7" Spring will get your spring perch to the middle of the coilover sleeve with a lot of room to go up and down
6" Spring will get you towards the top of the spring perch and you have to be cautious of coil binding in my opinnion.
Rear Setup
8" Spring will sit too low if you use a high offset wheel similar to stock
7" Spring will sit in the middle, high enough for wheel clearance (if that were to be an issue)
6" Spring will sit at the top of the coilover sleeve not allowing you to raise the ride height.
With the 8" spring, it's a pain in the ass (Front and Rear) to change springs when you have to pull that Koni rod just an inch (not a big deal if you only do it once, but when your changing springs 10x a year or more, it's a big deal for me) just so you can bolt in your struts to the camber plates.