From my perspective, 150MPH is possible. However, no RC car has achieved that yet (an a number of us are working very hard on it). So, 150 is obviously a very difficult mark to achieve. But, again, I think it is possible. The current world record holder (Nic Case) is a friend of mine. He has been in the 140s in testing, but hasn't topped that mark in competition yet.
Here is my take on what you are looking at;
#1 You need HUGE horsepower.
#2 You need extremely stable and slippery aerodynamics with modest downforce.
#3 You need high end foam or cap tires.
#4 You need a very good grasp of power systems and matching components.
#5 You need to be able to do the math required for gearing, KV to pack matching, etc.
#6 You need HUGE time to build the car and even more time to test it.
#7 You need a large amount of cash (maybe $3000 or so) to get the best equipment possible.
#8 You need long distance to run the car. This is one very difficult item because not everyone lives near a long, straight, smooth road.
#9 You need 1200 feet of radio range. This is also very tough because as far as I know, only the Futaba 2.4 ghz FAAST system achieves that without modding the radio.
#10 Did I mention needing LOTS of time and cash?
Oh, beyond that, you need a huge amount of patience and tenacity. You also need to like the car, but not love the car. The reason for that is, you need to be willing to open up the throttle. It is one thing to build the car, it is entirely another thing to successfully drive it at that speed.
Lastly, a ducted fan does not have the accelleration needed to push the car to the speed needed without running out of radio range and line of sight. The car needs to accellerate at 1.5 Gs throughout its run to achieve 150 mph without losing sight of the car.
Those are the challenges. What are the rewards? Well, very few people have exceeded 100 mph and only a small handful that have topped 110. It is an elite, close knit group. I am very excited to see another top speed contender working on a car. I would merely suggest driving the wheels rather than using a fan or turbine. That will give you the accelleration you need.
Of course, you could always use a rocket engine.
I wish you the best of luck. If you have any questions, PM me or ask here. I will be glad to help you in any way I can.