Sounds like a great car especially with such low mileage. Given the low miles and the fact that the car was garaged, likely driven gently, and also located in PNW moderate climate, I'd replace the TB at some point in the future but certainly not immediately. Given the circumstances for you specific car, and the ultra low miles, I'd likely wait until TB was 15 yo before replacing...that would be 2019. Just one guy's opinion of course...check out varied responses and make your own decision...there is a great amount of LS430 experience and common sense on this forum.

 

Early 04's had a transmission recall. Mine was replaced at 12,000 miles. Something about a parking lock inside that could fail under load. Maybe the nav too. It was a new release year.

 

I have been pondering this same question. I purchased a 05 which had 46000mi and now has 64000mi on it. I was told from the dealer nine years or ninety thousand mi. I will keep and eye on the water pump and bearings, and just wait awhile.