What is my Lexus LS460L worth?

I just wanted to get an opinion from my fellow automotive enthusiasts.
I have a dark metallic blue (it's called black sapphire) 2008 Lexus LS460L (that's the long model with a massive amount of rear leg room for the passengers) with a tan interior that I am considering selling in the near future if I can get a decent amount for it, but I have no idea what it is worth. The reason I am having trouble valuing it fairly is because any other 2008 (or even newer) that I've seen isn't even close to the condition of mine, and I've never seen one with as low mileage as mine....ANYWHERE.
When I bring it in to the dealership for my yearly safety inspection, the service writer always says how amazing the car looks. He told me that it looks better than the new cars they have on the showroom floor (it actually does). the car was never driven in the rain, or any other bad weather.
The car has 4,000 miles (plus or minus a few). Yes, it's not missing a zero. That's 4,000 miles!! and loaded with options including the 19" 5 spoke rims, Mark Levinson stereo, heated and cooled seats front and back, self leveling air suspension, Variable ratio steering, brake assist, GPS, self parking system and many more options. I still have the window sticker, The MSRP was approximately $84,000. (I can get an exact # if necessary)
The car is in as new condition, drives like new and even smells new, with no sign of use, other than 2 small chips that were touched up on the passenger side of the hood near the edge. They are barely visible, but visible if you look for them.
How much money should I expect to get for the sale of my vehicle if it was a fair deal, for both the buyer and me?
I attached a photo. Sorry it's a crappy iPhone photo that does not do the car justice, but I just wanted to show the car. Obviously if I was to put it up for sale, I would take nice photos inside and out with a SLR camera.
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Ouch!!!
At those prices I think I may have to keep it and use it as my beater car!
I had a Porsche salesman tell me that he would give me $38k on trade in. From what you guys are saying, it appears that he is giving me top dollar. As a matter of fact, with the tax savings, that $38k is actually $41,300. I guess if the salesman was willing to go "that high", his intent was probably to just tack it on to the new car
I was hoping to get close to $50k, I didn't think it would be so low. But hey, I didn't complain when I bought my Ferrari for 1\2 price when it had 3,500 mikes on the clock, so I shouldn't complain now either.

 

It's a long story, but I'll try and make it as quick as I can. I never bought the car because I fell in love with it, I bought it because it was an opportunity that I couldn't pass up.
I was in the market for a 5 series, CTS-V, or Audi S4. This car was my fathers car. He bought it new in 2008, didn't use it much because he went to Florida but left this car in NY. It was his toy so be never had it out in bad weather. He put under 1,000 miles in 2 years, and complained that he didn't use it enough. I joked with him one day and told him that I wanted to buy it off of him. Trade in price at the time was about $54,000 so I told him I would give him $50,000. I laughed it off and forgot about it. After a few days he called me up and said he would give me the car for $50,000 but he didn't want the money. He said to split it between the 4 grand children (2 mine, 2 my brothers). I figured I couldn't lose because 1/2 the money came back to my family (my kids), so essentially I got it for $25,000 and the other $25K still stayed in the family (my brothers family, it went to my niece and nephew). Essentially all the money stayed in the family, and was re-invested instead of giving it to BMW (or Audi) for them to invest. I had the car from 2010 to present, see below why the car has such low milage on it and why I want to move on to something else.

That's a good question, at one point, I had 6 cars so I saw no reason to use that one in crappy weather when I had a SUV at my disposal. I also had a period of time where I had a work car to go to and from work. Since my wife does more of the running around, I didn't really have too much of a need for it. As listed above, it was an opportunity that I couldn't resist. Yes it's a great car, but I would like to cut my vehicles down to 2. One sports car, and one family sports sedan. I would like to buy something more along the lines of an enthusiasts "drivers car". This car is perfection for luxury, but I'm still young and have time for isolated cars later in life.

 

I live on Long Island, I'm 1/2 way out on the island, and nowhere near the city. The car has only left the island one time to go to my friend's father's funeral. I would NEVER drive a nice car in the city (too many hazards for my liking). It was bad enough crossing over the NYC bridges to get to NJ!