swap 450sl '80 differential to earlier years?

I have a 1980 450 SL. I love the car and it is rock solid. After some upkeepin maintainence, like changing the injectors there are no problems with it. Well, maybe just one. It needs a little more acceleration. I know that the rear diff ratio was changed in 1980. Is it easy to swap to an earlier year diff? Does the diff need to be rebuilt first and with my input shaft?

1980 was the year that the 3 way cats were installed. If I changed them to free-flowing would there be a little bump in power, maybe not down low but in the mid and upper rpms?

Thanks for your coments

-brandjur

brandjur, I have a '79 450SL. One of the things I love about my car is the acceleration. At any speed, if I put my right foot down it GOES. I know you have less horsepower and more pollution control on yours, but I would think you could swap the rear end and get better performance. You might lose a little gas mileage, but big deal. I get 17-18mpg on the highway and the acceleration from 60-90mph is great, without going into passing gear, just slowly putting my foot down. Give it a try, good luck.

sbr
'79 450SL, 75,000mi.
milanbraun/ palomino
lake st. croix beach, mn.