2003 LS 430 With Mark Levinson and Navigation. Want to keep stock radio (i like the way it looks, I hate dash kits, and I use it occasionally for FM), but want to get rid of the ML amp. All door speakers are aftermarket and sub is next after I replace the amp and do some sound deadening. I also have a BT-45 TOY installed and would like to keep it.

I want to get an Infinity Kappa K5 Amp. It has bluetooth, but no volume control for the bluetooth besides from my phone. I have 3 possible ideas for what I would POSSIBLY be able to do.
1. Get an amp bypass kit and run RCA cables to the trunk, if at all possible.
2. Amp comes with speaker wire to RCA connectors, so I could either splice the inputs or the outputs directly from the amp, inputs preferably, so i can get rid of the amp. This is my favorite option if it will work...
3. Splice output wires directly at radio and send them to trunk, least favorite option.

Thank you everyone for help.