Info about Mugen's compatiblity with Asus P5K Deluxe:
Although Mugen is listed as compatible in the list I'd like to add that
Mugen with Scythe Retention Kit and without copper spacer is only compatible if the same capacitors around the CPU socket are used that I found on my P5K Dlx. If they're just 1mm higher Mugen will not fit and there will be much pressure on the capacitors from above (probably damaging the board). Mounting direction is irrelevant for this problem as capacitors are placed on two sides of the CPU socket.
Look at the pics for further details:
Mounting direction parallel to ATX I/O shield:
Mounting direction parallel to PSU:
Even with the fan installed it clears the RAM sockets quite comfortably:
If you use the plastic washers (quite thick ones) delivered with Ret Kit and the copper spacer from Ret Kit (a must if you use the thick washers) the capacitors could be a bit higher but the temps will be worse.
Bye Oliver