Yea, I think it was about $26 at O'Reilly's and $28 at AutoZone. They were within a block from one another so I bought the O'Reilly's and took it to AutoZone for a comparo. Side by side, very different. OR's was a copper looking one with large fins and the AZ was an aluminum looking one. I opted for the copper as it looked a little more beefy to my eyes.
Did some research and there wasn't an obvious winner.....different opinions. I did read that aluminum may have some corrosion issues when mixing different metals and the coolant. I figured, my radiator was copper so I should stay consistent with that.
Once I pulled the core out, it looked pretty identical to the copper one so that was assuring.
10 degrees here, I wouldn't attempt it today......
Couple of tips:
I unbolted the inner fender wheel well and pulled it down from the fender. I was able to gain access to the two bottom nuts on the bottomside of the firewall much easier.
Once you get the whole heater box out, there are two obvious screws that hold down the core. But there are also two more on the other end of the core....but they are under the foam perimeter strip.
Be gentle separating the box. The rod that holds the blending door goes all the way through on one side but the other side goes into a "small pocket". You can pull on the housing enough to get the small pocket side to separate.
Just take your time so you don't break any plastic. Good luck!