Here my final version of this image ( the wips are on Wip Area). :)
Original image rendered with 6K Width.
Corona V5. I got some crashes during the hi-res render using the V5 RC, but i guess there´s something with memory. But on the other hand, i have 32Gb of ram... A couple of times the render crashed on the Parsing step, but i just close and open the project again (Clean memory) and it render ok. ;)
PT + HD Cache.