Better maintain your 205/55/R16 specs since you want comfort as well.
Just change to lightweight rims & use either PS3, Hankook V12 or Yokohama C.Drive 2. Switching to 45 profile will definately sacrifice a lot of comfort and handling gains won't be much unless you want to use this car for track.

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Added on March 12, 2012, 2:52 pmGoodyear tyres are also recommended, especially their new F1 Series, but reviews have commented they are noisy, but handling is superb.
Can even be better than PS3.

This post has been edited by DSV4600: Mar 12 2012, 02:52 PM

If you die-die going for 17' rims, then please follow TRD specs since I saw someone posting it earlier.
For tyre choice, it's very subjective. One man's poison, another man's meat. For me, I'm a Hankook kaki.
If I can't find Hankook, then I would go for Michelin PS3 as 2nd choice, since I saw it in action at the 4G1 Series track day yesterday in the wet. Superb water dispersion & grip, even when tyres was almost bald.

For price of tyres, please refer to Tyre Price list here or at Autoworld.

I'm using Ventus V8 AKA V2 Blackbird. Superb handling & grip, wet weather is excellent.
My friend is using V12, same feedback, but even better. Sat with him yesterday as he speed around Dato Sagor in the wet.

If you don't want bumpyness or rough ride, trust me, stick to stock specifications (50 - 60) profile and switch to UHP (Ultra High Performance Tyres).

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Added on March 12, 2012, 5:11 pmIf you still feel unsatisfied, then switch to 17" after your new set needs replacement. At least you've tested for yourself.

This post has been edited by DSV4600: Mar 12 2012, 05:11 PM