If the Sony Xperia Z3 leaks were not good enough, the FCC has recently posted test completion of a D6603 Sony device. This model number is a step up from Z2's D6503 numbering, further lending credence to the Z3 being prepped from launch. The difference in this case however, is that where the Z2's release was largely staggered and slow especially for Western countries such as the US and UK, the early FCC testing suggests that Sony has plans for a larger simultaneous release worldwide.
The rationale behind this could be twofold. The first is to garner more awareness and therefore better share of the mobile device market. The Xperia Z2 while having excellent specs and design, was largely unavailable worldwide, which could have contributed to sales numbers being somewhat lackluster as users would probably switch to another device after waiting for a period of time. The other reason could be that Sony could be changing its strategy in which it limited the quantities and sells a premium device directly. This could be due to the realization that it is impossible to beat the likes of Samsung without having availability of said devices throughout the world.
With regards to specs, as the FCC's certification deals primarily with communications, the most that can be gathered is that the Z3 has dual-band WiFI, NFC, Bluetooth and data connectivity which doesn't reveal the more interesting hardware aspects of the Z3. As such, as of now, much of the Xperia Z3's specifications still remains a mystery. If the LG G3 and Samsung S5 Prime are any indicators though, chances are that the Z3 specs will be at minimum their equal. Here's hoping that the specs will blow the competition out of the water through innovation rather that minor specs bump ploy that most manufacturers adhere to so as to avoid having to do much.