I went with GROM and it's perfect.
I got the BT adapter with it as well so the phone connects wirelessly and play back for audio or video from any device is seamless. The USB connection accepts flash drives and Android/iPhone and there's a 3.5mm (headphone) cable connector if you'd prefer that.

To be clear, I do not think you should go the route of soldering the PCB. You will be risking the whole head unit rather than spending $150 on a clean, well engineered solution.

I had seriously considered GROM (as I had that setup on my 03 ES300) but was put off by the fact that there was information saying on the LS430 I would have to run an antenna extension from the head-unit all the way to the trunk. I am handy, but I didn't wanna risk the trim or carpet or other things not fitting well afterwards. I considered Best Buy installation but the fees they charge are ridiculous, in addition to an already expensive aftermarket headunit ($350), Metra dash kit ($30), amp interface ($60), antenna extension ($12), GROM kit ($206)= $660 total plus installation labor or time; or alternatively the $350 Beat-Sonic kit plus $350 headunit = ($700 total plus installation labor or time).

I paid $30 for the bluetooth cassette adapter and all is dandy!

I installed a unit from Grom last week, and it works perfectly. In fact, when I get back in the car, the music starts up again right where it left off. I have no idea how the Grom unit pauses my iPhone music when I shut off the car, but it does, and it resumes right where it left off when I fire up the engine again.

I never have any pairing issues. It pairs automatically assuming the radio is on when you get in the car. If it isn't, you just pull up Bluetooth settings on the iPhone and tap the Grom unit; it pairs immediately. When I get a phone call, I answer by pressing a button on my steering wheel; the music pauses automatically and I can hear the caller crystal clear through my car stereo. They can hear me just fine as well because I mounted the microphone up above the windshield right in front of my head (carefully tucking the wire under the headliner).

I installed it under the dash because there's not much space behind the stereo. Besides, I wanted to be able to get at it if anything goes wrong.

Very pleased with the purchase and the sound quality. (All of my music on my phone is ripped at 320kbps, so that helps.)

i purchased a grom unit. plugs in behind radio and i ran the cable on the bottom y the heared seats button. You play music and charge your phone. best of all its a usb so u can play any phone/music. nice unit

Im curious, does the Grom bluetooth display track name of the file on your phone onto the Nav Display?

Do you have the model # for the Grom unit?

Thanks!

I have the Grom BT3 with HD radio dongle. Can't say enough good things about it. Super easy install, and works and sounds fantastic.