Macbook Pro A1278 battery upgrade

As identified by serial number I have a Macbook Pro A1278 MC700LL/A early 2011 which is considered a vintage computer.

The OEM battery spec. capacity of the battery is 5800mAh 63.5

However, conducting research there is an indication the OEM battery for these Macbook Pro's can be upgraded to a higher capacity 6000mAh.

As per chat or telephone conversation with an Apple advisor they will never step out of the box and recognize there are component manufacture's in China who have engineer's who actually conduct test's in order to further enhance the the ability to upgrade several internal OEM components of their computers such as Hard Drives, Memory and Batteries. As we all know Apple does not manufacture their internal components and utilize components which have been Apple Branded and manufactured in China. Yes! I do agree and it possible Apple has set certain quality specification's for their products. However, I have come to realized these manufacture's are selling these same parts which are unbranded the term we use is generic which sometimes are Like Kind and Quality and some of course are inferior quality.

However, Apple support advisor's will never acknowledge this factor and will state a battery replacement for their computer's must be OEM and can only be performed by their so called Apple Genius's at one of their retail outlet's or through an Apple authorized repair facility. Anyway, enough said on this.

So, has anyone actually upgrade their OEM battery to a higher capacity battery?

Thank you for taking the time reading this post i do appreciate any response or opinion being provided.