Turbo boost would have to be a lot more than just the propulsion system itself.
There was that one cheesy music video floating around here that showed some of KITTs "landings" after he turbo-boosted. If you haven't seen it....well, it's bad. The front end of the car was pulverized by the crash.
Basically, for turbo boost it would require major and extensive modifications of the frame to make it withstand impacts from a certain feet. In KITTs case, we've seen him turbo-boost over chasms and airport hangers, let alone minor things such as walls, cars, rivers, etc. To make a car structurally sound and be able to handle the impact when landing from those heights, you would need either a new frame made of new material that would withstand that kind of pressure, able to keep the cabin intact and all other components of the vehicle intact and operating, or again, extensive and drastic modifications to the cars frame and support systems.
Next, consider the driver. When you hit the ground at heights of over two stories, it ain't a pleasant vibe (Not that I would know, but I can speculate), especially in the car. Either it would need to use some sort of air-cushioning system for the seat, or (dare I say it) the Passive Laser Restraint System so widely used in the last two seasons.....thing is, What the heck is PLRS?!??!! There are other protection systems out there, I'm just giving brief examples.
Then there's propulsion: Hydraulics wouldn't do the trick....unless they were small yet powerful enough to catapult the vehicle to the heights we've seen on the show. Perhaps a miniaturized VTOL (Vertical Take off & Landing) system similar to the ones used in the Harrier could do the trick, only super-charge the system to exhaust the vectors faster, thus propelling the vehicle further and faster. Rockets, as somewhat speculated on the show, could be used as well.
I won't even get into the laws of physics. That's just too complicated.
I think the other objective is space. Considering that you would need to make a structurally sound car with safety systems in mind for the passengers and driver, not to mention cramming in the propulsion system....that's quite an endeavor. Technology is getting better all the time, so who knows?
But just think, after you get the turbo-boost in, then you gotta cram in everything else!
