The one thing that has cost me most of my time and money is 'temporary' wiring/setups. Back when I didn't know any better, and started to learn about better ways of doing things I called them upgrades. If you are serious about your system and its performance, or are thinking of adding on later; here are a few tips that can help you out with both time and money in the long run.
Run your wiring once.
Think ahead.. are you adding another amp soon? a second amp or replacing the one you have with a larger one?
If so, go ahead and spend a little extra on larger wire and maybe a distribution block. Wiring kits are cheaper than individual components (wires, terminals, distribution blocks, RCAs, fuses, etc), and you are getting almost everything you need..ie, no last minute runs back to the store to pick up one or two things you forgot, or worse-taking a shortcut and leaving something out.
Use fuses where recommended.
My voice of experience is telling you that a car full of smoke is a dangerous thing. Put a fuse as close to the battery as possible when running power wires to the back of the car. I don't know what the specific recommendation is, but as a rule of thumb, I always use a fuse around 10% above what my equiptment is rated at. This will prevent damage if the power wire somehow grounds out before it reaches the amps. If you use a distribution block, use an inline fuse from there as well. My first setup didn't have this, and my power grounded out in the trunk causing the entire wire to heat up and melt the insulation off of the wire, filling the whole car with smoke. (Cheech and Chong visual)
Run your RCAs together, but away from power wires. Most quality amplifiers now have RCA inputs for every channel, so upgrades can be as simple as plug in and play. Use shielded RCA cables. An unshielded RCA cable is almost like an antenna, once the signal reaches the amplifier it has picked up alot of noise, and will inturn be amplified as well - causing alot of grief. A good shielded RCA is well worth the money.
Lastly, designate a good ground for your equiptment in the back. Use the same size wire to ground your system as you use to feed it. I like to use seat belt bolts to ground mine. Where ever you decide to ground your system, brush or scrape off the paint in that area to ensure a good metal to metal connection, and tighten the bolt back down tight.
Do it right the first time, and there won't be any extra time and or money spent on upgrades to your power or wiring.
