Overclocking on the 1155 chips is just upping cpu multiplier (leave the bclck alone as it's now linked to the iGPU), so it means you aren't reliant on the RAM being able to keep up with the FSB increases (because there aren't any).
I can't speak for the 3570K, but my 2500K was easily cooled at 4.6GHz with a thermaltake Frio, which seems to have shot up in price from the £30 I paid for it. I think the 3570K runs a tad hotter though so we'll see when mine arrives next week.
Let me know how you get on running FSX on it (assuming you still do!).
I have an i5 750 @ 3.8 at the moment but its around 3 years old now so the newer tech should help run FSX a bit better hopefully.
Well, they say filling up all of the RAM slots gives you less leg room when overclocking as it is putting more strain on the mobo. However some say it is a load of tosh and never have any issues getting good overclocks.
Personally, get as much as you want. 16GB (2x 8GB) is a good sweet spot these days.
I'm one of those who thinks it's a load of rubbish too. I've nearly always filled up all the RAM slots on my boards and it's never hindered overclocking.
It only tends to effect extreme overclocking, or when the mobo is cheap(for what it does).