so i forgot i had pre-ordered brink on gamestop and steam...so i was wondering is it possible to use the redeem codes for vice versa to get the dlc/specials?

I am pretty sure you can, if you don't need the key for the extra copy though.. I got a poor friend who could use a game, lmfao, (not me, I pre-ordered and fully paid off from gamestop, lol)

can you play the game without steam>?

yes i prefer hard copy of the game. but i dont see any redeem codes for the collectibles in the steam edition. so my assumption is i would have to use my hard copy redeem in the steam version?

I don't think you can get redeem codes on a hard copy of the game. I went thru this with borderlands DLC [I missed one! ERRR hate]. IIRC you need to have a steamed game [downloaded] to unlock it's dlc content.

No, Steam is required. I bought hard copy from Gamestop as well. The install puts it into Steam. To launch the game, you need to open Steam and launch from there. This is not the first game I got that has done this. Good news is that since it's run from Steam, no need to keep CD /DVD in disk tray to play game after installation complete.