Hey guys,

Is it a good idea to just add an aftermarket amp and sub and keep the stock speakers and headunit? I'm not looking for anything too special, just want more bass. I have the "premium lexus system" in my 99 GS400 (pioneer), not the nakimachi (spelling?).

 

Yes. Many have done it, there's a ton of info on doing it in the threads here. Try the search engine.
You will need a line-level converter (LLC).

 

thats what i did to my 98 GS 300 I have one 12inch Alpine type R and and a 800 watt amp with stock stereo. sound quality is good for the time being untill i install a component system in there.