Octavia I Infinity reference 6010CS 16cm or 16.5 cm for easiest fit.

Hiya

I'm considering uprating the speakers to Infinity Reference 6010cs but it seems people here use 2 different sizes 16cm and 16.5cm, which size fits in the Octavia the easiest with a minimum of fuss?

Do i need to remove the door cards when fitting these components?

I'm considering swapping the head unit and changer for a Kenwood unit I had in my last car, do i need an ISO adaptor to fit in the Octavia I.

Cheers