When I first did an oil change on my 2005 3, the perceived wisdom was that the under tray had to be removed. Halfway through removing said tray, having snapped off a couple of the bolts, I discovered, to the accompaniment of much cursing, that there was absolutely no need to remove the tray as the drain cleared the back of the tray, and there was a convenient hole for dropping the filter through.
Since then, I have avoided perceived wisdom like the plague and gone back to first principles - have a good look and a feel about.
I can't remember the exact details of the fittings, and in any case, mine may not have been original, as the tray, along with much of the front and radiators, was replaced after an encounter with a gigantic badger.
Replacement bolts? No way. Cable ties. I've had no rattles or vibration, and I know that if I ever need it off, a couple of snips and it's done.
The link below takes you to something that rings a bell - rubber insert and plug arrangement - but it's a few years back so I can't be certain.
https://www.amazon.com/Rubber-Screws-Deluxe-Push-Chasis-Black/dp/B003JBOBOI
