upgrading logic board to thunderbolt

Hi, recently my GF's laptop got wet, and her logic board is fried. I had just upgraded her system drive to SSD, and installed a 750gb media drive in her optical bay, and it was running great. :(

So, I am now looking to replace her logic board, and there is some great info on how to do so on here.

Here is info on here mbp:

-- late 2008 unibody 15" mbp (with mini display port)

Which leads me to two questions.

1. Could i take this "opportunity" to upgrade her logic board to a slightly newer model w/ thunderbolt?

2. What vendors have the best priced replacement logic boards?