195/60/15 and 185/70/14 both have the same radius(24.2") and they will provide the same road clearance. Their comparison..
Bigger side wall meaning more comfortable.
Less damage to suspension and rims in case of hitting a jump hard
No need to spend extra money to change the rims.
Don't look very pretty..
Better handling in a rainy day as they are less wider meaning more cutting through water
They look great!!
Better handling in dry conditions due to less side walls and wider
Not so comfortable on bad roads
Bad control on high speed where water is about 2" deep
Expensive.. Tyres alone and also you need to change the rims as well.
What tyres are you using now? I suggest you to change the tyres to 185/70/14 alongwith Al packing in rear tyres. As said by Mortal, you will get better road clearance than Gli. Dont get the packing in front wheels as by doing so you gonna loose the road grip and on sharp turns at high speed, its not safe.
And vitz is not as fragile as you are thinking.. Its a very nice and durable car.. It does not shake on Motorway when going at 140kms/h whereas Honda city is only good upto 120kms/h.. After that speed you must be a very good driver to control it.