from memory, the Bilstein B6 will just reuse the stock bump stops and if not i think your mechanic should be able to source these easily. I think used bilsteins is fine BUT as with any second hand coilovers/shocks, you really need to know how much wear they've had, how old, how many KM etc. Get your Bilsteins from Gary (SK), i think his contact details are somewhere around on this forum, he has direct contacts there - i got mine all 4 delivered for approx 1000$ a few months ago and that was when the AUD was on top, now, i don't know how much it'll be. but give him a yell.
King springs are around 300$ more, so all up, it should cost ~1400$ give or take.