Why are Turbos so much better?
To answer this question, you have to have a good understanding of how a turbo system works.  Click on the
turbo above for a great "How Stuff Works" article on turbo systems.  A properly designed turbo system
is clearly the best choice for a high performance street car.  Here are some of the advantages of turbos:

Adjustable Power Output:
This is probably the best thing about a high horsepower turbo car.  As you may have read by now, a turbo system
uses wastegates to vary the amount of boost the turbos create.  A boost controller can be used to change the
amount of power your car is making with the simple flip of a switch.  The ultimate in power control, is our AEM engine
management system.  This computer replaces your factory "brain" and can be setup to deliver the perfect amount of
power. 

Here is an example of how we would set up the power delivery of a stage 3 twin turbo viper:
1st Gear - 550rwhp
2nd Gear - 700rwhp
3rd Gear - 850rwhp
4th Gear - 1000rwhp
5th Gear - 1250rwhp

You can see that as you go faster, more power becomes available.  This makes for a much better driving experience.
It can be pretty frustrating to have a huge 1000+ hp moster that just spins the tires every time you squeeze the throttle.
Here at Heffner Performance, we make huge controllable power.

Efficient Design:
As you probably know by now, turbochargers are driven by the engines exhaust energy.  When you are not in the throtte,
the wastegates remain open allowing the exhaust to bypass the turbos as if they were not there.  The point is, when you
are not in the throttle, the car has the fuel efficiency of a stocker.  A supercharger, on the other hand, is powered by a
belt that runs off of the crank.  It is always "spooling" no matter if you are in the throttle of not.  This results in extra
unnecessary heat build up, and poor fuel economy. 

                               
A turbo will make more power than a supercharger at a given amount of boost, because it does not require engine power
from the crankshaft like a supercharger.  Also, a turbo has a much better boost curve than a centrifugal supercharger.  You
see, a supercharger has a direct connection to the crank.  The only way to make the supercharger spin twice as fast, is to
spin the engine twice as fast.  This results in a linear boost curve.  This is a disadvantage, because, as the graphs above
illustrates, the only time you are making peak boost is right before you have to shift.  This results in a "peaky" dyno graph
that falls a little short in the mid section.  Now if you look at the turbo boost graph, you can see that the turbo spools to
peak boost, and the wastegates open just enough to hold that peak boost.  The result is a lot more power throughout the
entire RPM range.  In fact, it is not uncommon for a turbo car to make 200+Ft./Lbs. more torque in the 3500-4000rpm
range, than the same car supercharged making the same PEAK power numbers!  So be careful, because peak numbers do not tell the whole story.