Not sure how to post pictures but here is one of the threads for the 50i models
https://g05.bimmerpost.com/forums/showthread.php?t=1732018&page=4
The 40i models have a single exit pipe vs the dual on the 50i and it looks like the 40i single tip is actually oval at the tip and not round. I haven’t found any slip on or clamp on tips that have an oval inlet to fit that oval pipe. I am guessing one would have to cut off the oval part but I wasn’t sure that would leave enough straight round pipe left for the tip to grab into. I hate how you can see the stock tip inside the trapezoid bumper opening so easily stock, sticks out like a sore thumb.
Any other 40i owners find a way to fit a tip?