It sure is easier to clean 20's than 18's, and I find the ride to be super.

 

The 20 in Pirellis on my C2S are night and day smoother than the 19 in PS2s were on my 08 RS-60 Spyder. Then again, the 19 in Michelin SuperSports that replaced the PS2s were too.

 

Really? Wouldn't the ride be affected by the absolute distance from the wheel to the street? Also, wouldn't that affect the potential for wheel damage on potholes?

 

Yes, that's part of it. But remember that the suspension is quite different and that affects ride quality even more.

The 991 with 20" wheels rides smoother than my Cayman S with either 19" or 18" wheels. And the Cayman rides way smoother than my 993 4S with 18" wheels.

Also, the sidewall height differs with size of 'tire' chosen. A small sidewall height is pretty much a given on the 20" wheels, but this is not necessarily much, if any, less than those found on 19" and some 18" tires.

 

Colors are very personal choices. Between the two choices that mentioned, I can only say from experience that the black/black/black is a pain to keep clean. (Also the wife acceptance factor of the b/b/b may also be an issue).
As far as the options, you will find several threads in the 991 forum dealing with options.
I am not sure where you are located, but your location may determine certain must-have options (heated seats in Chicago for example or cooled/ventilated seats in Florida). I have 20 inch tires in the 991 and do not think that the ride is harsh (I used to drive a 997 cab with 18 inch tires before that). Keep in mind, that you can go crazy with options and that most likely, you will not get that money back when you get rid of the car.

 

I drove a 2014 Cab S with the standard 20" wheels. It is absolutely true. The 20's ride great. So here's the problem. I like the S much better than the base! I'm committed and I am going to change my purchase to an S. Black, black with black interior. Thank you all for your fine advice!