I was originally told back on my Series3 that 1tb was the largest recognized by the Tivo. I now have a Premiere XL4 and I see weaknees offers a 2tb external drive. Is there anything special that has to be done to use a 2tb external drive? And is 2tb the maximum external size for the XL4? Also, is there a compiled list of working external enclosures for the Tivos?