I have to replace my 07 R56 battery, any suggestions?
I would like to replace it with an optima but not really sure which size would be the right one 34R or 34/78.

 

The 34r is the right fit but some people have installed the 34 backwards and run the cables around. The 34r will make for a cleaner install.

 

I ended up getting a Bosch battery with the same specs as the mini, I dont like the fact that has the venting port.... but it fitted very good and took me like 5 minutes to replace.
next time I will replace with the optima.

thank you