Here is a render of the Audi Q3 for its 2018 model year. The Q2 will be out by that time so the Q3 will be growing in size. It may grow from the current 172.7 inches to somewhere around 177 inches.
The 2018 will likely shed some weight as well as it will be riding on the second generation of the MQB platform.
When it comes to the engine, this 2018 Q3 will have an engine lineup that will be quite similar to the VW Tiguan. There will be a gasoline and diesel engine as well as a frugal plug-in hybrid derivative part of the e-tron family. There should be a RS Q3 model too.