JBAs are a very good street-oriented choice as they bolt in place of the factory Iron exhaust manifolds and they increase power across the board.
That being said, the Long Tube style headers offer even more horsepower and torque gains than the Shortys, but require you to replace the factory mid-pipes as well.
Also, with headers a big selling point is Primary Tube Diameter. The larger the tubes the more ultimate HP and TQ the header will be able to comfortably support before being a potential bottleneck to the system.
So the JBAs have 1 5/8" Primaries and there are 2 different models of long tubes offered in both 1 3/4" and 1 7/8". As with many bolt on go fast goodies all the parts have the potential to make serious power, but most do so by trading low end torque for extra power at the peak of the RPM band. Also with headers, i have seen it written in header related tech articles its better to go slightly small on primary tube size than slightly too big.
The 1 5/8s JBA shorty headers dont make as much peak power as, say, a 1 7/8s long tube header. But the JBAs will still increase your low end torque and provide you with good throttle response over the factory iron manifolds.
If the application is a mostly stock daily driver that sees some towing, my personal suggestion would be the JBAs.
If you prefer the long tube style of header more I would suggest the 1 3/4" primaries over the 1 7/8 unless you were looking to use a stroker motor later, forced induction, large cam etc....
here is an excellent article by David Vizzard on header sizing and why.
Hope this helps you