Wheel fairings
I've owned my 150M for 29 years now, and all that time the wheel fairings have been collecting dust up in the mezzanine of my hangar. In truth, they were not the right colour, as they were retained from my previous 150. I'd never really fallen in love with the look of the fairings, and I used to do enough rough and mud runway operations that they would have been a less good choice. But now, the 150 is more of my airport to airport commuter, so the fairings were worth a reconsider.
So I had them painted, and put them on for the first time. Knowing that I anticipated this, I took a note of cruise speed with bare wheels over a couple of recent flights. 2500 RPM at 3000 feet 10C got me 98 MPH IAS.
So last evening, same power, altitude and temperature, I was happily startled to see 107 MPH IAS! The performance chart does not specify wheel fairings, but as all the pictures of the aircraft in the POH show the fairings installed, I presume that's the way Cessna thinks of the plane. And, the POH value of 108 MPH TAS corresponds nicely with what I have observed. That was sure worth the effort, I wish I'd done that years ago!
So It'll be a bit of a faster summer and fall, until winter snow demands their removal for that season.