Okay I have a 2005 ES330 with mark levinson and nav. How if possible do I set subs up to the head unit? Speaking there is no RCA output port? Can I hook up subs to the factory head unit?

 

You need an oem interface hooked up to stock amp to create an rca line....

 

Bringing this back to life as I'm in the same current situation.
Haven't found anything after looking for about a month.
I was able to use a LOC to add a aftermarket sub and amp to my BMW E39 and would like to know if the same can be done with the ES330.

 

Not sure what you mean by "haven't found anything" - do you mean info in the CL threads on this?
You can use a LOC but the better way to do it is to get a mono sub amp with high-level input(s). You'll have control over gain, which you'll need to adjust output relative to the rest of the system. I'm not that familiar with the ES - if it has a "sub", you can just use those wires...but if the bass is filtered to whatever speakers they're using for bass, you'll be missing some sound. I'd play some test tracks to see what the existing system is capable of as far as low freq extension, unless you can get additional advice from someone on here that's done it.