Complex sentence: Katz quickly replaced PKARC with PKPAK and, soon after that, with the new and completely re-written PKZIP, released as shareware, which compressed both better and faster than ARC.
Split into simpler sentences: Katz quickly replaced PKARC with PKPAK, and soon after that, with the new and completely re-written PKZIP. Released as shareware, PKZIP compressed both better and faster than ARC.