the EZ
I have experience only with the EZ, but it plugs into the engine wiring harness and map sensor without removing any 'void' antitamper stickers.
The increase in boost is accomplished by working on the wastegate elbow. The factory setting for boost is around 20 psi, the elbow modifications allow much higher boost, up to about 32psi in my truck.
The EZ connection that plugs in between the map sensor and the factory plug to this sensor 'adjusts' the signal to the computer to keep it from turning on fault codes when the boost exceeds 21#.
There is a significant power increase without the extra boost, the extra boost is extra air, which significantly reduces EGT's. So the boost elbow work is not mandatory, but is recommended: it reduced my EGT's by 150 degrees.
The EZ box changes the fuel timing which gives much better throttle response. The box also adds more fuel, and this creates fun

!!
I chose the EZ since it seemed from several days of reading and watching this board that the EZ was the most popular box in use, therefore having the best and quickest resale value. [In case I didn't like it] But now that I've installed the EZ and driven with it: don't try to buy my EZ box, it is not for sale!!
I'm sure that the many other boxes have their pros and cons, but I wanted a box with no tattle-tale marks left behind in case I needed to remove it and take the truck in for warrantee work.
Warning!! adding and using power is ADDICTIVE! Just check my signature!
JMHO, enjoy your new power! Greg L