Hi RavenPearl
I believe you're over thinking this. Dealers are there to make money. You're there to get the best deal you can.
If you are emotionally attached to a particular bike then you will pay more. Salespeople (in whatever field) are trained to press those buttons.
I bought a brand new Honda in the UK for my wife and got 12.5% off of list price and a set of waterproofs thrown in the deal. If I had gone to a discount dealer I might have got 20% off. But I wanted it to be local so she could ride in and get a bit of TLC when the bike needed servicing during its warranty.
My own bike I bought secondhand and privately because I was able to do basic servicing and there was no warranty aftercare involved.
Your "blue book" in the USA is probably about right give or take up or down for mileage accessories - we have similar in the UK - that I suggest is where you want to be.
Make an offer and walk away. You can always swallow your pride and go back the next week because it will still be there if it's overpriced! If you are close to the salespersons minimum deal he will come after you with a better offer.
Ticket price: £6000
Salesman "£5000 - it's my very best super duper price, my boss will kill me!"
You: "I really want it but I've only got £4,000."
Salesman "Sorry can't do it."
You: "I'll go a way and think about it." (SALESPEOPLE HATE THIS!)
S. "Meet me half way then ..."