I'm about to hack my GH2 and, unless I'm mistaken, I can't add both the 44 MB/s improvement and the 176Mbit I-frame improvement on the same camera. If that is the case, do you feel the 176MBit I-frame hack is much better than the 44 MBit? How reliable are these?

FlowMotion (v2.02?) is my general preference. It includes a 50Mbps 24L setting and 100Mbps 24H setting, and both are dead reliable (spanning, 80% VFR, etc) with the most moderately decent cards (ie Transcend Class 10)

I haven't had much use for the 150+Mbps patches

I use the Vanilla 44mb/s and have a few issues recording complex scenes like fast running water despite using a Sandisk 95mbs card.
The pictures at 44mbs are stunning and stable otherwise. I personally wouldn't use the higher hack as I feel there are stability issues, plus editing flow issues, plus the fact that unless you are shooting big screen TVC's or features there is no need for that resolution in your final product.

i love GopStoppa, no any issues, except for the 8min clip limit and you need 95Mbps card,
but the quality is amazing, sometimes you can't tell where is what:)
Panasonic GH3, GH2 and Scarlet in 24p - YouTube