Thank you for your thorough review, Victor!
The M24 oil cooler sells for $1,840. Off topic a bit, we've wanted to develop a manual dipstick for the S65 for years, but have not been able to create a solution that does not involve removing the oil pan. Pulling the pan is very labor intensive and for this reason we have not been able to bring anything to market. I also would kill for a manual dipstick on the S65!