That is an amazing hourly rate for a Mirage. The airplane is ok. It is very small upfront, and has a very thin wing. At gross weight in the heat you will eat up 3,000 feet before the thought of rotating even crosses your mind. You can then plan on about a 500fpm climb.
You will have anywhere from 1200 to 1400 pounds of useful load with either 120 or 140 gallons of fuel. I cannot remember the zero fuel weight, but you are only taking six people if they are small and UPS their bags...or you fly over weight.
You will burn 35gph in the climb and 20-23gph in cruise. In the mid to low teens you will see 185kts TAS, 195kts in the high teens, and 200kts in the lower 20s. I did see 215kts TAS at FL250 once, but can count the number of times I went above FL200 in it on one hand. I don't think I ever took the plane into the flight levels with passengers because of the poor climb rate.
Alex.