Is one necessary? I realize that it will take the oil longer to warm up, but does one make that big a difference?

I'm cosidering two right now, Permacool's and Mocal's Sandwatch Adapterp.

Permacool's cost less, but isn't as simple as Mocal's. If I use SS lines (which I don't think I will right now) Mocal's makes more sense because it would require 4 less fittings!

Recommendations?

 

Given your climate I would definitely want a thermostat. I have successfully used the sandwich type adapter on several cars - no problems there - if it really fits the Max. You might try Summit or Jeg's for a lower price.