Out of curiosity, I ordered both the Toyota 90118-WA263 "Screw plug with o-ri" and BMW 33117525064 "Differential Drain/Fill Plug". Both of them came with a pre-installed o-ring, and neither of them had a crush washer. ?‍♂️
Serious question, why not reach out to race shops that specifically cater to building drift cars? Someone like Seems Legit Garage would probably know the most direct way to address the issue. You definitely wouldn't be the first person to ask them how to fix wheel hop on a BMW chassis.
If they...
look into the bimmernetwork heat shield if you want an option that doesn't require delicately balancing a bunch of spacers that you'll inevitably drop during the install.
https://www.bimmernetwork.com/products/bn-b58-intake-turbo-heatshield
Honestly, I wouldn't model one from scratch if this already existed for $20. There's no way I would be able to get it done in 10-20 minutes, which is what a typical hourly rate for our day jobs...
when you switch back to OEM operation, you need to shut down the car to get it to save for whatever reason. I physically got out of the car and locked it to make sure it would stick.
i disabled the BC button operation in the jb4 menu after I figured that out.
there's a guy on the track mkv group in Facebook that has a aj hartman wing attached to the anniversary edition holes. that would be a much better user of money in terms of downforce per dollar
If you look closely, the vent is like 80% blocked off. Everything NOT in a blue box can't flow any...
His rear toe has side-to side variation of 0.02 degrees. I would bet real money that if the alignment tech were to roll the car off and back on, there's a good chance to it would register as dead-on. and yours would come back as misaligned again.
since you noted that the rear traction arms had the largest effect, you could also replace the upper trailing arms that run parallel to the traction arms. These also resist thrust loads from the tires, though counterintuitively, I think they are loaded in tension when you're accelerating (?)...