Help

- I can't make my mind up whether or not to get the V+ box.
I really don't need a second box but don't want to pay £75 for installation (I'm not sure that I understand why moving the original box costs nothing even though extra cabling will usually be needed but replacing an existing box costs £75???).
If I go for it can I just keep the second box in the same place (at £5 per month on XL TV) then get rid of it after a while or do I have to keep the second box for 12 months?
Will I see a worthwhile picture improvement with the (admittedly limited) HD on my 720p/1080i projector which has to be connected via an adaptor through the Projector's PC In D connector, I think.
Is there a limit on the length of cable that can be run from the V+ to my projector and does the HD signal degrade over a short distance?
I wonder whether I should just go for it but any advice is welcomed