If you want a good Ghibli it will be around 12-14 grand for a GT & 18-20 for a cup.
I have not yet seen a better example since I got mine just about a year ago, 32000 miles two owners etc. It was up for £13,000 but once BM hade done a full inspection I gave the report to the seller & we agreed a discount. Still needs a small amount of paint to get it just right but unless you find a show car this is always going to be part of the ownership experience.
I had to compromise on colour over condition and since the 1st big service bill to sort the car, running costs have been almost nill. Needs an annual service now but that will be minimal.
The Light metalic blue cup that's been for sale for about 9 months has a very used interior & high milage although well looked after. £16995
The red cup is much lower miles good service history, but again from second hand knowledge needs a little work to paint. 16995
I have not seen the Grey one so can't make comment, but the colour combo is very nice again around £17000
So in all honesty book price for a GT is going to be around 5-8 grand but in reality a good example will set you back as much as a well used cup. If you can find one.
To sum up they will be much more collectable than a QP in years to come .