There is no basis except a vendor was looking trying to find ways to sell products. I posted photos of the stock drain ID, compared to the "high flow" drains, when he first offered them. Stock were slightly smaller. A drain is a very simple device, it allows oil to gravity feed back to the block. The N54 stock drains are MASSIVE for the amount of oil a properly set up N54 turbocharger is moving through it. If you have oil backing up in your N54 turbos, there is a real reason behind it, and adding "high flow drains" is not going to fix it...
I just so happen to have a set of "RB HIGH FLOW DRAINS" here because a customer brought them to be installed, I showed him the measurements, and I showed him how poorly they fit, getting in the way of the front water line etc. He agreed they should be thrown into a box and sold on the forum.
Measurements
Stock Drain ID: around 12.55MM
RB "High Flow" Drain: around 13.85MM
Difference of: 1.30MM
Take a look at what 1.3mm really is in the picture attached.
That he charges $225 for a part that literally does nothing is a testament to good marketing... Unless your stock drains, are ruined, or for some reason unusable, there is never really a reason to change them. Its a stainless steel pipe with stainless braided hose.
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