how i should go about thislexus is250

It's been a while since I've been on this forum, but the last time I posted it was regarding a sound processor for retaining the OEM head unit. First off, my car is a 2009 Lexus IS250 with navi, non ML. I am not a professional installer, so please bare with me. I was considering the JL audio cleansweep CL441dsp, and I believe in one of my old posts someone told me it was meant for tapping into a full range signal. I was also reading elsewhere that there is a Soundgate product that is meant for tapping into a signal AFTER the factory amplifier. My assumption is that if I did tap into a signal after the factory amp, I would not receive as great of a quality signal as if I did tap into the full range signal? Furthermore, I honestly think that I'd end up with a rockford fosgate 3sixty. Now, with this product, would I tap into a full range signal, or can it be tapped after the factory amp and receive a good signal as well? If anyone on here has a wiring code for my model year I would greatly appreciate it as well. Thanks in advanced all

Unless you have an adapter that gives you access to the line level output from the HU, all of the devices you mention use speaker level inputs so they are connected after the factory amplifier if the car has one.  Then you must supply after market amplifiers to power your speakers.Support the12volt.com