Truma water conversion kit.

Old firefighter

Can anyone advise me on how simple it is to convert the original Truma water inlet & pump with the  'TRUMA ULTRAFLOW COMPACT CONVERSION KIT- WHITE - 46030-03' I've found on Ebay at £34.  We are currently having problems with our 2004 Lunar Stellar water supply pressure, & understand this conversion should make a big improvement. Any advice welcome, thanks !