yet another battery question

[rbcski]

Hi all:
firtst time here, but been a long time member of the other site, I have a 2001 x5 3.0, need to replace battery, but the only battery I can find is from walmart everstart 49-1, this is spec for x5 4.4, does any one know if this will fit - hate to bring it back and forth. also the tech in walmart said I need to get a "radio code" from the dealer in order for my radio to work after disconnet the power, is this true ?
I did search the archive, nothing about 49-1 fit for 3.0.

Thanks