I'll buy them from you!
- the balljoints seem to last a long time. I have the original ones on my X/19, at 186,000 kms now. The driver side is quite good - no play, the passenger side has no play - but is easy to move around, most likely indicating that it's nearing the end of its useful life. I'd imagine that they can be rebuilt by epoxy injection (I haven't found anyone in Canada who does that though). The balljoint rides on plastic inside, lubricated.
If the boot rips, grease leaks out - and fails early. But if the boot is in good shape, try to miss Toronto potholes - then they should last a long time
FYI - The left side control arm on the later cars are slightly different to clear the 5spd transmission. Since you have a 5spd conversion, make sure you have that control arm on the left side (it's got a folded section on the upper side of the arm)