All, I need to replace the fuel selector in my Cherokee and see that Allen makes both the NON-PMA and a PMA model. What is the difference in the part itself? If my mechanic tells me that he is fine with the NON-PMA one and he can install it with the 337, is there a reason I should be concerned? Are the parts inside better on the PMA one... or is it simply paying for the the certification process on that one? Thoughts? The difference in cost is 184 dollars vs. 409 dollars for the part. Thanks!