These tools can help you save you a lot of time when working on N54 and N55 engines:
CTA Tools 9226 E-Series U-Joint Torx Socket-E10(almost a must-have when replacing the oil filter housing gasket):
https://amzn.to/32RGCtR
GEARWRENCH E10 x E12 Torx Double Box Ratcheting Wrench - 9221
https://amzn.to/2O8J5fg
Technically not a tool but silicone spray is great to have around when working around O-rings and silicone couplers:
https://amzn.to/2PagAOk