3.29 means the sun gear in the diff is 34 teeth 3.05 for sung gear is 38 2.86 for sun gear is 42

so if u call the dealer and tell is that the final gear ratio is as above that means both sprockets drive/driven = 35 teeth only 35/35=1 so diff matter only.

the above is the gear ratio of the differential , mainly super charged 3.8 are the issues also the ones goes on AWD units, some have instead 37/33 sprockets in (awd) it has 33/37 sprockets and that will be counted towards the final gear ratio and will be different than the above three mentioned, you can swap diff in most 3.4 and 3.8 and 3.5 as long u match the pins in the main connector, some but rear seen heated treated sun gears as only in volvo with such transmissions, either volvo or GM all the same and better stay away from shift kits in general and only use if needed the kit only for the atf valve in the channel plate if worn . so bottom line the word enhanced does not mean better but specific final drive gear ratio

Salim Safran
Owner/Engineer
Transmissions 4 Less Co of America
Chicago, Illinois, USA