Before 1958 (I think it is) and the introduction of the 500 version, the Commanders didn't come with the stainless steel/aluminum wing spar sandwich which caused galvanic corrosion and is subject to a 36 month inspection still (unless your remove it with an STC), so the early 520's and 560's don't need it thankfully. I do however have to subject it to a 5year/500hrs prop inspection, which is quite costly. Thankfully mine was done 160 hrs ago and has some time left on it.
I'll look into the autolean feature. Most experts have warned me not to ever lean manually, as it cooks the motors when you add your own lean on top of the barometric autolean system. Perhaps with good monitoring, like a JPI system, one could combine the two for optimum performance.