$500 seems to be the standard rate. Usually they do dealer prep - detail the car. The car is usually extremely filthy upon arrival. You could ask if they could not do the detail and have your own guy do it and they may cut the price further.
2014 BMW ///M5 Individual Frozen Grey, Silverstone Full Merino, Piano Black, Exec Pkg, Drivers assistance plus, LED Pkg, Bang and Olufsen, 20" 343M Forged Alloy Wheels
Countermeasures: Bel StiR+, Laser Interceptor Quad HP, Zaon MRX
Upgrades: Eisenmann Sport with M Performance Carbon tips, Dinan anti-roll bars
2015 Jaguar F-Type R Coupe