Alloy Wheels for Accent Executive

I have decided to buy alloy wheels for my black accent executive car. I have the following doubts,

1. Which brand should I choose... I came across Plati, Apollo,......Is there is other good brand ?

2.Can I increase the wheel size from R13 to R14 ...  What is the impact of this on my car performance ? Will my mileage change ?

3. Where in Chennai can I get a good set of alloy wheels for a good price?

Any of the brands will be fine.  When you're selecting wheels for a family sedan, there is no criteria other than looks.  I believe the Apollo wheels are very well made and therefore more balanced. 

With the 'imported' rims that are brought in by unknown 'importers' you never know if you're getting a new rim or a completely reconditioned one.

Anyway, go by what suits your car (since your vehicle is black, I think chrome or chrome-trimmed wheels will look good - very bling-bling).  Yes you can upgrade to R14 (no issues - I've done it), but you need to have the budget for new tyres too.

To add:

No practical change in terms of FE, ride and road holding will depend on the tyre (if the same is also upgraded).