The .6 needs electronic control and is much different than the .3 / .5. The .3 / .5 has a neutral / backup switch by the shift lever where the .6 does not. The .3 and .5 are much closer to each other than the .6 is to either.

Looking at better pics of the .3 and .5, the .5 might be slightly longer bell housing to drive shaft flange but the mount location looks the same. In any event, the added length should not be an issue as the driveshaft can easily be shortened..