If it's a real Motorcraft part it's fine. I've bought auto parts from Amazon before, you just have to check to make sure you're getting a real part and when it comes in make sure it's sealed in OEM packaging.

 

I've seen some on there that are like $20... I'm not really one to pay for a name just because but when the factory part is about $60 and some no name company, or one that ships from China is selling the "same thing" at 1/3 the price I get nervous. If it's not name brand aftermarket like Riffraff Diesel or whoever you prefer or Motorcraft, I'd probably avoid it.

 

Here is a link to the last couple blue springs I used, or the one with the cover if you need it.

Alliant Fuel Pressure Regulator Blue Spring Kit (AP0086)

Ford Fuel Pressure Regulator Blue Spring Kit w/Cover - Riffraff Diesel Performance

 

I buy almost all my parts from amazon. I usually only buy the ford or motorcraft brand though. Still almost half the dealer cost for the same part. There are some aftermarket products that would be OK but for example I just bought an egr valve and it didn't fit. Wouldnt seat and the metal was not as strong. Return policy Is great with Amazon too.

 

A fuel pressure gauge is strongly recommended, that way you can buy a cheap spring and not worry about it.