Cross forest migration from 2008 R2 domain to 2003 domain

Hi,

Due to business reasons we need to perform a cross forest migration for around 20/30 users however the domain we are migrating to is still a 2003 domain (DL & FL).  We are a currently run 2008 R2 domain (DL & FL).

Will we experience any kind of issues with this?  It's a odd scenario but needs to be done!

Thanks,

Shane