Physically, it's a straight swap (Just a lot has to come out to get to the diff)
Worth checking first. There will be a white sticker on the base of the diff with the ratio
Calais being a luxury model likely had a 2.92 ratio diff for fuel economy, so putting in the 3.27 will throw out the speedo/transmission, which would need a re-flash to the new ratio
I swapped out the 3.27 Open Diff on my VF2 SV6 to a super low KM LSD (3.27).
You have to remove exhaust, tail shaft, then each axle. The manual says to remove the axles from the knuckle. They are done up to over 300Nm and are a staked nut that is likely rusted, so be prepared for a **** fight.
In the end I removed the knuckle with the axles attached. Some people say to remove one side then lower the diff slightly and the other axle should come up but Im dubious if that would be worth it. Plus you run a higher risk of damaging the seals and CV boots. On your replacement Diff, id get new drive axle seals as well.
Got the job done over 3 days on axle stands. It nearly broke me but glad I done it. Bit the bullet and did the whole 9 yards, new Centre bearing, Tailshaft couplings F/R, Transmission mount and axle seals for the diff, cause I sure as hell don't want to do it again. The bolts on the tail shaft are TTY so should be replaced (Which I did cause im OCD on my car) but others probably don't. If your car is high KM, id do the above whilst you've got the drive train apart.
Im very happy with the results. I can certainly tell the car surges forward with more composure under hard acceleration. Worth it compared to the usual Exhaust/Tune
