hi my point of view, maintain ori size.. u can always get ur rims repaired.
or u can opt for lighter alloy wheels...  make sure u invest on good tyres.. 15" tyres are affordable..

i am using 16' inch.. without any major mod,
change rims,
change tyres...

but mine from previous model, manufactured 2005

16" - less comfy.. + tyres price much higher.. if looks, 16" better.. but make sure u use light rims. if not ur car wil be carrying xtra load..
xtra load = less power, higher fuel consumption + more stress to under carriage components = bush n other stuff, kong faster..

as mention, it is not the brand that need to look into, its the specs of the rims,
larger rims, more weight, hence lighter one should be better....as explain by chrislyv

i forgot brand that i used for rims, but for tyre, i use falken ziex....

at first, feel the different of the car position, which is a little bit higher.
other than that not much different... as of feeling....
find that the fuel consumption a little bit higher...but this does not necessarily contribute by rims factor alone...

overall, 16 inch is better in terms of appearance, and performance for now...

workshop near junction at jalan gombak towards jalan pahang.  junction to kg puah,
i find that this is the most reasonable price of rims and tyres i can find around KL.
while they also buy my previous rims and tyre at higher price as compared to other workshop...