I would not trust those at all.
Fdm is a horrible idea for an intake part. A draft on the room can cause issues with later adhesion and you can end up with crap in your engine. I mean I could use an fdm printer and make them for less them $15 each shipped. Problem is that fdm you are asking for issues.
Issues are fdm parts are way to week for anything I would trust in an intake system. Petg glass transition temp is 80c and is 105c pla is 65c. And you really don't want that plug to get soft.
I don't want anyone to have a plug. One apart and get sucked up and destroy there motor because some site decided to buy a $100 3d printer and make parts. Firewall plug is fine but anything in the air intake system you need to test and know what you are using. That's why I went through a process of testing the resins to make sure they can withstand the heat but also the cold and rapid thermal cycles.
Anyone selling you an intake plug ask then what temperature the meteral has been tested to and what process they used. Also ask about thermal cycles. Because I can go get some cheap petg fillament. Hook up an fdm printer and cheap fillament, humidity, drafts that intake plug will be inside your engine.
But if you guys are going to roll the dice here ya go.
https://www.thingiverse.com/thing:3267691
Send those files to shapeways and have them do e on a high-end printer in nylon or reinforced nylon. Abs will be about the same but it will be done on a $20,000 printer not a $200 printer. Or if you just don't care local collage you can get it printed cheap or find a guy online by you with a printer and have it done for $10.
Just keep in mind abs and pla require some control to keep the layers from splitting after a while. And they get soft at some pretty low temps. Combine those and it's a really bad combo and something I would never put in my car let alone sell.
Personally if I needed one and didn't have my SLA printer with the right resin and didn't wanna dump $150 for a bottle of it. I would just have shapeways do it on there multijet in PA12.
Not trying to steal a sale. I'm an engineer and I'm giving you some information that you might not know and an option to have it done right. Don't risk your car on a cheap part. We don't need to go back to the days of eBay "chips" and resistors that go into your mass airflow sensor plug to "increase power" Critical systems require some R&D and there's the right meteral for the job. If you need one use that file off thingiverse send it to shapeways and have them make it out of the right meteral. I won't upload my files because I want control over the meteral they are made out of so it doesn't crack or come apart and cause engine damage or falure. It just takes one time and some unlucky person is now $8,000 in the hole because gm will find abs plastic in the engine.
I really don't wanna see anyone draw the short straw and eat $8,000. This is one of the times I wish I could offer a quality alternative that has absolutely zero risk of falure even if you put a clam on it and over tighten it but I have other projects that require attention and I just ran out of time.