OK here's the skinny, I did mine last summer, and it sounds great, no missing beats, haven't blown any speakers (yet!!!) but I also don't push it to the max. Trust me it cranks very well. I have an jvc 200 wattx4 mp3/cd deck. It sounds amazing. I also wired off the deck a mtx mono sub in the trunk (just one 10). The new deck doesn't bypass the factory amps it adds to them. I used the wiring harness from Wal-mart (I'm sure the crutchfield would be the same). Now some people say to use the adapter also sold at walmart that lowers the voltage of the new deck so not to have any problems with the factory amps. I did buy this, tried it, and I did not care for it, so I took it out. Now My deck is a competition deck and I think its a 2amp deck, not sure if that makes a difference, it may, and I have no problems without the special adapter. I did however have to wire a resistor (can't remember size, do a search on the topic and you will find the one) into the factory amp turn on lead to prevent a poping sound when the factory amps turn on. This is because you have a 12 volt turn on wire from the new deck and the amps only need like 5 amps to turn on (That's what I was told from an old post). After I did this no popping sound and no problems. The system sounds great for being factory speakers, I'm sure the sub in the trunk helps out majorly, allowing me to cut down the base to the door speakers and just use them as highs and midranges. All I can tell you is that you may need the adapter depending on your deck choice, and the wiring adapter from eitehr crutchfield or wlamart. But if you don't bypass the amps you will get a popping without the resistors wired in. I'm very happy with the sound, and have had no problems. Hope this helps