Here's my current running configuration...
Scorpion HK4020-1350kv
Castle Talon 90, bec at 8v
MKS HV9767 cyclics
MKS HBL980 tail
Vbar
Rail 516mm and 80.6mm
Head speed 2700rpm
Pulse 4500 45c 6s
Matt's running the same except for BLS 276 Tail, CGY750 and Thunder Power 4400 70C packs.
Pictures attached. While not completely fair to compare the 516 to a stretched E5, these pics will give a sense of scale next to the E5 frame. Notice the meaty parts are much smaller and lighter, more appropriate for the 516. Overall, it's not significantly smaller than an E5, but it is much leaner throughout. Still waiting for my canopy!!!!