From their advert:
Supercharging is the best way of getting more Torque and Power from the Chev 6.5 diesel engine.
Advantages over turbocharging
1. Easier Installation :nono:
already have a turbo just need a better turbo ATT is bolt on

2. Less Underbonnet Heat
based on what comparison 6.5 na vs. 6.5 turbo ?
3. Cylinder head is prone to stress cracks with turbocharger
subjective claim IMO 212k crack free miles thus far on mine
4. Kit is available to suit left or right side Air cleaner
5. Suitable for marine applications
Boost is adjustable by changing the supercharger drive pulley size. Kit comes with 7psi pulley.
Turbo makes this and then some
Basic Supercharger Install Kit -
$4900 

Includes Custom manifold
Supercharger with snout and drive pulley
Rear Supercharger entry manifold (left or right available)
Needs idler pulley and drive belt to suit your application.
Rubber hose to your Air cleaner
Injector pump needs to be re-calibrated
Full Supercharger Kit (to suit engines with serpentine belt) -
$5600 

For that kind of $$$/work you could have twin turbos and be 150mph+ capable like Bill Heath
Basic kit plus modified mounting bracket for Air Conditioner compressor
Full installation instructions.
Needs Vacuum pump pulley machined (approx $60)
Rubber hose to your Air cleaner
Injector pump needs to be recalibrated
Advert looks like 2007 last update, is this a current advert ? if one had their own supercharger handy and the requisite fab skills it could be done I'm not sure the bang for buck would be there, Detroits I used to work on in my USNR Hatteras cabin cruiser was both turbo & supercharged rite around 500hp ea X2, but unlimited cooling water for the engines and inter and after coolers from both the turbo and the SC.