To expand on Bill's expansion :), replacing the rotor cap requires unbolting the old one and swapping out the new one.  I would get the seal kit, too. It's only 8 euro or so. Includes the shaft lip seal and a replacement bearing.

Every A54 seems to be different (!?!?) but to use the Marco on mine required me to buy hose barb adapters. I got these:

https://www.ebay.com/itm/Male-Thread-Pipe-Fitting-x-Barb-Hose-Tail-Connector-BSP-Stainless-Steel-ark/253006828611?ssPageName=STRK%3AMEBIDX%3AIT&var=552054492119&_trksid=p2060353.m2749.l2649

I got the 3/8" BSP x 15mm barb. The BSP end is for the pump and the barb end is for my existing hoses. You will need 2 of these.

--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com