Sorry fellas and girls if any out there, I well confused, on the realoem site it states my 30.d needs a 90ah

So for the x5 3.0d 2005 the battery i need the equivalent of the below:

a) Original BMW battery, filled 90ah part number 61218381768 or
b) Original BMW AGM-battery 90ah part number 61216924023


Okay i call the local distributor of bosch and he says my vehicle takes the 100ah and will be fine, he also says he supplies bmw dealerships on the island too...fair enough, issue is I have read that sticking in a higher rated battery can lead to electrical gremlins....yet according to another post here bosch suggest the 100ah battery ? confused or what

Just called the dealer and he has 90ah listed for use in the 3.0d and nearly twice the price of the bosch