Before I upgrade my ROM what settings do I need to write down?

[abmw]

I am on Sprint and was going to upgrade my to NSFANs ROM. What settings do I need to write down. I know when I first got my phone and had problems the service reps told me to press a sequence of keys to get to a menu to show the MSD values(I think thats what its called) Could someone tell me what the key sequence is and if those values get overwritten when I put in a new ROM.

thanks