Icon check my sig, I use an Apogee GT block. The leftmost corner rubs against the VRM 'sink fins, but it still fits. It also works fine with the CrazyCool backplate left on.
If you meant watercooling the NB... the DQ6 NB cooler is still downright cool to the touch in most places, even the VRM fins are cool due to the case fans right next to them (P180). I see zero reason to use a WC block on the NB! All "heatpipes" have a liquid in them, they would not function without it.