Will 195/55/16 be a more cushy ride compared to 215/45/17? I'm guessing so but not sure.

 

yes. Also some tires are softer than others due to sidewall construction, so if you find a touring/comfort type of tire in 16" it will be softer still.

 

How comfortable a tire will be for a given car depends on many factors including tire size. But that alone is not always enough.

A runflat in 195/55-16 is going to be firm riding compared to a non runflat all season tire in 215/45-17.

There are many tires that are firm riding or more comfortable in both tire sizes.

In general Grand touring All Season tires will give you more ride comfort for street use.

In addition there are other tire sizes that will work besides the ones you mentioned. You can also look at 205/55-16 but tire selection may vary with which size you choose.

What tires where you considering? Why the different tire sizes specifically?

Note that 215/45-17 is not an OEM MINI size, 205/45-17 is.

 

Minihune, I was thinking of going down to the 195/55/16 because the sidewall is taller which might result in a softer ride. I have a set of 16x7 Rota RB's with two like new tires, I'll have to check the brand.

 

OK, but lets look at the bigger picture.

If ride comfort with street use is a priority then-

I assume you have OEM suspension (sport option?) with no plans to lower it.
Your roads are OK, not perfect but not full of potholes regularly.
You have OEM 17x7" wheels and 16x7 wheels to choose from.

Do you plan to use these tires in any cold weather (less than 38 degrees) or in any snow?
Do you have a budget?
Do you care if treadwear is 350 or less or would you want longer treadwear.

For 17x7" wheels and OEM suspension-
205/45-17 or 215/45-17 are the tire sizes to look at first. Select tires that are less stiff in the sidewall if comfort is important. If you see that the tire is XL load rated, it is constructed with a stiffer sidewall to tolerate a heavier load than a tire of the same size.

For 16x7 wheels and OEM suspension-
You have lots of possible tire sizes to choose from, 205/50-16 and 205/55-16 being the first places to look.

In general the tire you choose has more to do with ride comfort than the tire size given the sizes that have been mentioned. Grand Touring All Season tires as a class will give a smoother more comfortable and quiet street ride with good treadwear, good use in any weather including light snow, but you will give up some handling vs Max or even UHP summer tires.

Example of tirerack test results from Grand Touring AS tires-
http://www.tirerack.com/tires/tests/...y.jsp?ttid=166
http://www.tirerack.com/tires/tests/...y.jsp?ttid=171
http://www.tirerack.com/tires/tests/...y.jsp?ttid=152

Best bet is 205/55-16 which gives these options:
http://www.tirerack.com/tires/survey...wws=N&showcm=N

In 205/50-16
Pirelli Cinturato P7 $109+ each
General Altimax HP $88 each

In 215/45-17
Pirelli Cinturato P7 $138 each, 700 treadwear
Michelin Primacy MXM4 $160 each, V speed rated, 500 treadwear
General Altimax HP $95 each closeout, 440 treadwear

For those that want better handling and still good treadwear and usable in three seasons then look at Ultra High Performance All Season tires-
see:
http://www.tirerack.com/tires/survey...jsp?type=UHPAS
Continental ExtremeContact DWS comes in sizes for both 16" and 17" wheels, starting from $112 each, 540 treadwear, and gives comfortable ride and three season use.