There should be absolutely no issues if you take your Hyundai Eon for a drive of 175 kms. The mileage you get would depend on how aggressively you drive. But on an average you can extract 18 to 20 kmpl.
There are many options available for a 2 DIN music system for Hyundai EON in the market. You can check with a local car accessory shop to know about the options in detail. Also, you can check out some options on our online shopping portal. Please find a link below to check out the music systems http://shop.cardekho.com/car-accessories/music-systems.html