sharpest wideangle to normal zoom at f8?

Hi All,

I have recently gotten an e-m5 and found a love for doing night cityscapes. I am currently using a panasonic 14mm to achieve this and it seems plenty sharp for me at f/11.

However, lately I've been itching to get a zoom lens to vary my picture styles abit more, what would you consider to be the sharpest zoom lens at f/8 + ? ofcourse the first thing I thought of was the Panasonic 12-35mm, but it seems quite a few people are dissapointed with its sharpness and CA, how does it compare to the panasonic 14-45mm? or oly 14-42mm II R? I heard both of those were sharp, which one would you choose to shoot at f8?

Cheers!

Eric