Our interest was in a managed dedicated not only for the support, but because we will be putting Battlefield games on the server mostly. Would a managed dedicated receive those tweaks you are mentioning and in addition, if new hardware became available, would we be able to upgrade or would we have to move to a new server to get those benefits? And one final question, if we had to move to another server to receive hardware upgrades, would we be able to keep our IP's so that gamers wouldn't lose our server in their favorites list?
Yes a managed machine would receive most of those benefits. A dedicated machine is just about exempt from special upgrades. It is possible, but that is something you would need to work out with John as it requires him buying it and then having the data center install it, which also cost money.
A VDS machine can be moved in some cases to a faster machine at it's location but it really depends whats free in that location. If you to move a machine all files and IP's would go with it, assuming it is a managed machine.
Usually when people look in to purchasing VDS or dedicated machines they are doing this because they know what they want and what they are getting. If you were to purchase a VDS I would say do it because you need it and not on the assumption you can be put on a faster machine is one becomes available, as usually this is not the case.