In most cases you don't need server-side drivers for your printers. Most people can get away with installing drivers on the client side and using so-called raw queues on the server. In some cases it is convenient or necessary to use Postscript drivers (or no drivers at all) on the client side and use filtering queues, queues to which a server-side driver is attached, on the server. This is particularly true for mixed networks with Unix/Linux clients that don't have any local spoolers/drivers installed, Mac OS X workstations, and AppleTalk clients like Classic Mac OS or BeOS. In Windows-only networks you normally don't need server-side drivers, though some people do prefer using them.
Both LPRng, the standard printing system in SME Server, and CUPS can use raw queues and filtering queues, but the framework for using filtering queues with LPRng is a bit more involved than with CUPS and not present in SME Server.
Some people also find that CUPS is easier to use with unusual printers, like serial and SCSI printers, or printers shared in a Windows, AppleTalk, or Novell network.
If you have a parallel, USB, or ethernet printer and only intend to use raw queues, there's usually no need to change your printing system.
If you have an unusual printer and/or wish to use filtering queues, installing CUPS is probably the easiest solution.
If you do decide to install CUPS and set up a filtering queue, don't install the driver that you mentioned in your post. Instead go to
www.linuxprinting.org and look up your printer and find out that another driver is the preferred driver for your printer.