The two in the front are fairly easy - all you need is a couple of wrenches and some extra brake fluid to bleed them afterwards. You can probably knock them both out in less than an hour. The rear one on the other hand was a big pain in the butt, just because it's kind of hard to get to, but overall I think I did the whole thing in less than 2 hours. You'll probably notice a difference even if you only do the front ones, because that's where most of your stopping power is.
Calmini Cone Air Filter, PowerVault PV2 Muffler, OME Trooper Springs, Rancho RS9000X Shocks, 285/75R16 Nitto Grappler AT's, Pioneer DEH P8000R In-Dash CD, Amps and Drivers Built by Orion, Wires and Fuse Blocks by KnuKonceptz, Vibration Damping by BQuiet, Alarm System featuring Auto Start and Remote Windows, Yakima LoadWarrior w/Full Size Spare, Debadged/Custom Titanium Grill Logo, Tint (5% Rear / 20% Front), Steel Braided Brake Lines, G2 Painted Calipers