Northbridge cooling and after market cpu coolers

I just build a new system around the P6T D V2 MB. I'm going to replace the Intel stock cooler with an aftermarket one so I can get a moderate OC. Unfortunately the Scythe Mugen 2 cooler I bought I had to RMA (the plate was concave!). I need to purchase another. After looking at the board and seeing how the Norhtbridge heatsink seems to be made for a rotary cooler like the stock one, will a tall cooler cause the Northbridge to overheat? I've read that it runs hot with this board anyway.

so three questions. Should I get a Northbridge cooler? Suggestions on which one? Also, should I install the fan that comes with the board? It says to use only with watercooling or passive, but I'm not sure if an aftermarket cooler would make this viable.

Thanks in advance!