Im curious if anyone has added a clutched fan from a 300D to a 240D?

There are two 300Ds in the junkyard near me and I'm hoping that by adding the clutch fan to the 240D it will quiet the motor down a good bit on the highway?

Only thing I wonder is if the engineers knew most people would be driving the 240D at full throttle for extended periods of time and therefore figured the fan should just be turning all the time to keep the motor cool?

I love my 240D but the motor is so loud at times it can be headache inducing and I wish it were hair quieter.