Mobius - don't know if the same info applies to the Koni's, but my sachs kit came with a cut front bump stop (about ~ 1/2 what the OEM one should be, I think) and on the rears, I used the OEM full sized bump stop and dust cover. No problems to report on that configuration as of yet, thankfully
I would definitely use a dust boot of some sort, esp if your old ones were "caked with dirt".
Best, whit