CAI Filter Adapter for Mini Cooper S Stealth

This piece is used to mount a K&N cone filter inside the stock airbox. The John Cooper Works (JCW) performance option has a similar intake from the factory. The mod is invisible after putting the box back together. I also used a holesaw to enlarge the stock cold air inlet in the bottom half of the airbox and the cowl. You'll need a 2.5" grommet to seal it up, I happened to use the r53 lower steering column boot I replaced the day before, it fit ABSOLUTELY perfect. I'm sure you'll need a tune to properly see any power gains, but the noise difference alone makes it worthwhile.:) The supercharger screams at WOT, especially with the window open. It used to whine loudly under throttle blips, and now it does not, suggesting that it is indeed breathing better. There is a tutorial for how to do this modification available online, they used an ABS plumbing elbow. I bought one but didn't like how it sharply necked down in the filter opening. This one has about 10% more diameter at it's narrowest point and the inside has smooth blends and transitions for the entire length. I printed it in PETG for fatigue resistance. ABS would be my second choice.