Go on! Spring for the Eagle Mike part!
What you'll get: A magnet adhesion that won't likely come off in your crankcase. Besides a proper internal length, you'll get a, "low-profile" recessed external protrusion, also, with the Eagle Mike part.
Why are these features worthwhile?
1. A magnet bouncing about in your crankcase poses obvious risks; the automobile plug you buy at Auto Zone or Pep Boys or NAPA for the smoother, more vibration-free automobile engines--magnet-to-plug glue adhesion of the car version not that critical.
2. The low-profile Eagle Mike part is less likely to strike a rock and crack your case, as the longer-extending automobile plug might.
Your bike; certainly your privilege to modify it as you choose. However, in my view, buying a low-budget plug locally, just to save a few bucks in shipping costs, may be, "false economy," an example of outsmarting yourself.
By the way; just how MUCH is the shipping charge for the Eagle Mike oil drain plug?
Finally, the geometric advantage of a low-profile plug while riding in a rock garden appears an easily grasped concept. A magnetic plug? Nothin' ag'in 'em, but far from essential, in my view. The oil filter's capable of capturing lots of trash; even non-magnetic contaminants.
“You better put down that gun. You got two ways to go, put it down or use it. Even if you tie me, you’re gonna be dead.” "John Russell" (Paul Newman), Hombre