I don't know if you have to pay sales tax, but without tax, the numbers seem to be like this:
With setup fee of about $1000, and no destination charge, the new one comes in at roughly $39,500. Then subtract about $1000 for the jacket and first service, so you're getting the new one for roughly $38,500. You said a difference of $8,000 after your trade, so they're giving you about $30,500 for your '12 (Is that with the tour pack on it? If not, that's another $1000 or so in pocket.) So you're getting pretty good bucks for your trade-in.
Based on numbers shown previously shown on this site, the dealer paid about $32k for the '15. They can sell your '12 for around/+ what they are giving you for it. Then there's what you'll spend to get the new one where you want it.
But those are just the numbers. Only you can tell if the non-money benefits (looks, comfort, reliability, performance) of the new one are worth what it costs to get them. That can be a tough wrestling match. Good luck.