When they(BMW) replaced my instrument cluster in my 2001 X5(build 12/00), did that upgrade my low OBC to high OBC???

From reading the threads here, if I want to upgrade my NAV to a MkIV, I would need a high OBC.

Any suggestions where to purchase a MkIV nav?

Thanks

__________________
Mark _______________________________
2001 X5 4.4i topaz blue/sand Sport, complete Dinan S2 , hitch, V1, tint, BSW Stage 1, Alpine INA-W910BT
___________
Life is not fair!
You can't protect people from their own stupidity!
Laughter makes life worth living