I've been eying the iOSD mini for a while, but never pulled the plug because I was on the fence about the upgrade board or PMU-V2. They cost about the same, and there was no clear winner. I dropped 9g from my mainboard, so the upgrade board would have been ~17-20g heavier. On the other hand, the PMU-V2 was 28g by itself, but could probably be lightened up a bit. I went with the PMU thinking that if successful, I could cut out the BEC from my mainboard and run it as a pure PDB, else I'd have a workable PMU module if I transfer the Phantom's guts to a new quad. Turns out the PMU V2 can go from 28g down to a meager 8g. Whoa. The iOSD predictably drops from 16g to 4g. Paired together, that's 12g. With necessary connectors and wiring, 15g total. iOSD and PMU stacked to the right side of the NAZA. Four layers - RX, mainboard, PMU, iOSD. That's a lot of blinking red/green lights in a 1cm^3 volume. Final weight without batteries: 884g. With my 4400s, it's 1205g (looks like I may be looking for ways to shave off another 6g). With my 5400s, it's 1280g. At that weight, I think I'm officially off the market for a 3-axis gimbal. Just not gonna happen if it means going over 1300g. The iOSD is fun, now I don't have to draw out distances on Google Maps or guess how high I am. First test flight is hopefully tomorrow, if the weather cooperates.