Okay Guys, my finaly analysis on the S550 compared to my 02 LS430. The 550 has gone back to Forida for a while. 1000 miles in 13 hours. DRIVING FOOL..lol.. As you could tell, I was impressed with the 550. Just took a spin in the 430 and will tell you, for the money, a fine machine. Hence, the money, the S550 is probably the the height of auto engineering inside and out. Keep in mind 5k miles versus 72k miles and 5 years. If I was to buy today and had an extra $25k I would choose the 550. Don't know the 460 and have never driven one, but have seated myself in one. Not at all more impressive than a S550. The finest auto I have ever driven, and I have been in a few. The 430 is like a comfort zone and "reliable". $25k difference, If you have the bucks then a S550...We will wait and see the reliability of the 550 versus the 460 but as of now, for the bang for the buck step up to a 430...from your 400's, you will "not" be disappointed. I hoped I have served you well and will keep you posted on both cars.