Upgraded to GH2 from GH1 - some questions

Bought the GH2 today at Park Cameras as a replacement for my sterling GH1 - she's been great over the years, but I wanted a bit more dynamic range and fast focussing. Anyway, I've been looking through the manual and settings, and have some questions which I hope you can answer/contribute to:

1. What does I.Resolution do? The manual isn't very specific.

2. Is Long Shtr NR beneficial? I'd have thought most noise could be dealt with in PP.

3. Is it better to save to sRGB or Adobe RGB? Apparently the latter has more colourspace available - would this be visible/usable in LR4?

Thanks for any assistance.