it's not too hard to do your own. i did mine-no problems thus far. just get some nice big fat cables, (like 0 guage at a welding supply place) because apparently there's a bit of voltage drop in a longer cable. bigger=better current.
One of the best places to find power distribution stuff is at your local car stero hut. Any shop should have everything you need and the prices usally are'nt too bad. But you can save money by buying welding cable over buying some cool looking shiney stereo cable.
Will the Optima batt vent for any reason? i know it says 100% sealed, but is there any circumstances that it would vent. Because since it would be in the back of the suburban i want to know if i should get a sealed box or if it's no big deal.