Repercussions of Raising Domain Functional Level to 2008 on Mac computers running 10.6.2 with OD

We have recently replaced all of our 2003 server domain controllers to 2008 r2 and have tried to implement PSO's but have found that the domain functional level must be raised to 2008. We have a mac server in our environment that runs open directory and it is integrated into AD. Does anyone know if I do raise the domain functional level (which makes sense since we only have 2008 r2 domain controllers) what the repercussions (if any) there will be on the macs in the environment? Macs are running 10.6.2 and mac server runs the same. Mac server is running OD and also bound to AD.