As you can tell I am a newbie to AcuraZine but am well competent when it comes to audio/visual installations. I have spent many hours searching the forums and have not found much information on upgrading the OEM 2003 TL-S HU with an aftermarket one while retaining the Onstar system (for the phone feature). One member actually posted a similar question almost a year ago (https://acurazine.com/forums/audio-video-electronics-navigation-22/kenwood-dvd-hu-03-tls-wiring-assistance-needed-onstar-nav-314623/) and there has not been a reply yet... Maybe someone can shed some light on this issue as I am sure many people that have the Onstar systems in their TL's faced the same problem.

Alpine actually makes a speaker (Alpine KAX-551) which is suppose to accept the navi/onstar input (not sure exactly how) and allow for an aftermarket HU upgrade. Has anyone had any experience with this piece? I found one for $100 but am skeptical as to how it performs. Has anyone successfully upgraded their OEM CD player with an aftermarket one WHILE keeping the Navi voice and the Onstar? (I actually could care less about the Navigation voice prompts, just leave me Onstar phone!)

I will definitely be getting rid of all the speakers and that p.o.s thing they call a sub and replacing them with a complete system. The speakers in the 03 TL are a JOKE! I have always had component speakers since my first car at age 16 so the thought of listening to the paper door speakers makes me cringe. But as mentioned, the only problem in my way is the Onstar system... I can easily add an amp, 4 components, and subs to the OEM HU but it obviously lacks features and controls of today’s aftermarket units. Any information will definitely be appreciated.

Thanks in advance!