New owner of a 99 GS400 and wanting to upgrade the head unit. I know nothing about wiring but I am aware the factory amplifier will have to be bypassed. My question is, can an aftermarket amplifier replace the stock one? I think the stock audio quality is really good and I want to be able to keep the speakers while still having a working amp. Will an aftermarket head unit + amp work with stock speakers?

 

Congrats on your purchase. I know with the proper maintenance you will have many years of worry free enjoyment. Now to your questions...

1) can an aftermarket amplifier replace the stock one? To my knowledge, no. I believe that the head units in the 2001 - 2005 GS uses a Can-Bus system to communicate with factory amp. The volume, fade, balance, bass, mid and treble are controlled within the amp and cannot be substituted with an aftermarket amp. I'm pretty sure its the same with the 98 - 2000 models too.

2) I think the stock audio quality is really good and I want to be able to keep the speakers while still having a working amp. Will an aftermarket head unit + amp work with stock speakers? Absolutely!! There are many options available for aftermarket head units both in single and double din sizes along with nice looking dash kits. Most head units and amplifiers come with active crossovers which will allow some control of your stock speakers to maximize their sound and output. I would run at least 14 gauge speaker wires to the stock speakers especially if using an aftermarket amp. Good luck.

 

What is it you’re hoping to achieve with the stereo project? The stock stereo can sound pretty good to most people, but if you’re really wanting a premium stereo system then you’ll want to start over with a replacement head unit, aftermarket amplifier and speakers. The factory system is designed specifically for the speakers and the vehicle, so each speaker receives exactly the frequencies that the speakers were made for. Trying to replace any part of it piece meal will leave you disappointed.