I'm just trying to understand what controller you have at your main/production site. If you have say a FAS8000 series and you're failing to a FAS2554, there's a problem IMHO. So you have a 2554 at both sites? I'm just trying to understand what systems you have in your environment.
As far as a head swap goes, there are two types. Online, also referred to as an ARL or the offline method (hard down). Controllers with internal disks can't do ARL headswaps. Ther'es also a lot of compatibility checks that go along with headswaps in general.
That said, I'm pretty sure you can't headswap a 25xx between and a 27xx. It's for sure nothing i'd recomend for my customers.