I recently had an Alpine CDA-9857 installed in a 2000 TLC after the factory 6-disc changer died. The installer didn't crank the engine or he would have heard the engine noise. So he ended up bypassing the factory amp (sort of). He said he put some of the low frequecies through the factory amp because the noise was not noticeable.That did not make a lot of sense to me. The stereo just sounds really flat and begins to hurt my ears after extended listening. They have told be a new amp and speakers would sound great and that it would fix the engine noise (surprise surprise). I don't have the money to spend on speakers and an amp at this time. I know some of you on this board have had success with aftermarket radios going through the factory amp. The installer said he tried many different grounding techniques. Am I wrong to think the factory speakers would sound better being powered by the factory amp? Any grounding suggestions. Could someone confirm the correct wiring harness for a 2000 lc w/ a 6-disc changer? The installer said he used the MAD TWH-14. But it seems some threads on this forum say that is only for the single disc players. I apologize for writing so much for a first post, and I did read and search a lot before posting. I am just confused and frustrated. Any help would be greatly appreciated.