The tom arms that come with the kit should work just fine with the Pearl PCX-100
tom/cymbal mounts that come standard with the rack. The basic "front-side only" rack comes with 2 of these, the 3-sided rack comes with 4 of them. Here's a link to the 3-sided rack so you can see what it looks like: http://www.musiciansfriend.com/drums...rved-drum-rack
If your kit comes with 2 Mapex tom holders standard and the add-on tom doesn't come with one, then you should order another matching tom holder for that 8" tom.
Depending on the number of cymbal arms that you have, you might need more of the PCX-100 clamps. The rack comes with 2 cymbal mounts that attach to the tops of the vertical pipes, so there are 2 more places for cymbals right there.