Mugen fits on the ASUS M2NPV-MX without any problems, despite the fact that I bought Mugen on my own risk (because only guess about possible compatibility with M/B)
Also Mugen is compatible with Inwin S564 with airduct removed.
Maybe, the first RAM-slot could be blocked or even couldn't be installed when you are using high heatspreaders, ordinary ones could be installed/uninstalled ok.