I am a former Grease Monkey from my High School Days, when working part time at a gas station. I have some knowledge of auto maintenance.
I just returned from Sam's club, was going to get them to change the battery in my 2012 Mini Conv., but they were a little concerned about the rubber trim at the bottom edge of the wind shield when you take the plastic shield covering the battery. I called Flow Mini and believe it will cost around $279 (Parts/Labor) to replace a battery I think I can do myself for about $150.

I also looked at a "how to" online and this is what I found:

Question. Is there anything I need to be worried about in replacing the battery myself? Is this rubber gasket against the wind shield anything I need to be concerned about?
And, should I use a battery tender when replacing the battery in a Mini?

PS. I was really planning on doing this myself anyway, but the guys at Sam's Club got me a little concerned about the rubber by the wind shield, not the rubber gasket under the hood that needs to be removed.

Daniel Miller.