I needed to move one of my Turbo parts cars and remembered that I gave someone the fuel relay pack (2 rubber covered relays above and behind the right front strut upper mount) I found what I thought was one in my partsbox but 2 are needed so I went to buy one - long story short, I searched around and started thinking, "Which auto manufacturer would develop what is essentially a really cheap relay when they can buy an existing from supplier's that they know.." and ran into a picture of what looked like one and then checked others & connectors and a lot of relays look similar and have the same plug on the bottom so I took a chance and bought http://www.ebay.com/itm/Airtex-1R1084-F ... 0708943866
for $22 delivered. I took it out of the box, looked exactly like the Sprint part and there are actually 2 to a box, so I plugged the new ones in and the car started up - so winner. Incidentally, bought a door/window relay with the same plug and it works too, just no rubber cover.
I was also working on a customer tour bus and the mechanic couldn't get Napa to find the right parking brake shoes and they were like $100 for similar ones++ so I took my new found knowledge of just looking for a part almost by site and discovered a set that were $35 delivered. Bolted right in.
So: lesson learned, they don't reinvent the wheel, they just charge customers what they'll pay. Similar story is an older Lamborghini needed some very expensive brake parts and someone took to their Cheap British parts supplier and got the same parts but at WAY cheaper prices. Sourced from another manufacturer, I read recently that Ferrari 308 parts were fro some pretty pedestrian cars like the 914.