It would make more sense to have more tutors for artifacts in decks instead, since a tutor for artifacts can search for both Vehicles as well as other types of artifacts (hint: Boommobile can combo off with two other artifacts Cogwork Assembler and Panharmonicon)
In trying to concoct a deck for Cazur, Ruthless Stalker and Ukkima, Stalking Shadow, I quickly found myself going back to old-school Commander decks
But Class abilities can be anythingstatic abilities, activated abilities, or triggered abilities
Not all Planes are created equally
Costing six and not being able to immediately gain any life means you will have to do quite a lot of work just to get to stage you can make the Wurmcoil with any semblance of safety, if at all
This isnt the only way you can build Muldrotha, however