TTX ball joints are very good ball joints and are made by Mevotech.
Mevotech parts deliver extreme performance for high usage commercial and passenger vehicles.
I've had great luck with TTX ball joints on my truck and they've lasted over 50,000 miles.
You should grease new ball joints before installing them.
Although you only need to grease new ball joints a small amount as they are often greased some from the factory which also prevents corrosion during shipping and storage.
You want to add just enough grease to fill the ball joint without overfilling and potentially damaging the booth when you install the ball joint under load.
You do need an alignment after replacing ball joints in some cases.
Replacing ball joints can affect your vehicle's alignment significantly and potentially lead to uneven tire wear if the alignment is not adjusted properly.
However if the ball joint can be pressed out of, or unbolted from the control arm then the alignment shouldn't change after the ball joint replacement.
You should replace all ball joints at once if you can afford to do so.
Once one ball joint starts to go bad then it's often soon that the other ball joints will also fail.
However if you can only afford to replace only the bad ball joints right now then that is also okay.
But you should also plan on replacing the other ball joints as well eventually.
Replacing all the ball joints at once also ensures a more consistent and safe suspension system.
Ball joints that are on the same axle also tend o wear out at similar rates, so if one ball joint on the same axle fails then the others are likely not far behind at failing.
Replacing only one ball joint can also affect the vehicle's alignment and make it necessary to get a re alignment after the ball joint replacement.
Replacing all the ball joints at once can save you money in the long run by preventing the need for any future and multiple repairs later on.
You will find that ball joints on each side of the vehicle tend to have similar wear, which means it's common to have them replaced in sets or matching pairs.