lorax - 2:08 am on Nov 18, 2011 (gmt 0)
Welcome to WebmasterWorld!
It can be cumbersome to apply your design to the new CMS as you'll need to learn where everything is - and then there's the issue of porting content, 301s, and rebuilding the index authority and link juice you might loose from the switch. Impossible? No. Time consuming? Quite possibly.