Yes, it has settings for 1 1/2" material.
It has a lifetime drill guide warranty. Not sure about the other parts. I've drilled hundreds of pocket holes and the tool works just like new. I've only had to replace the driver bit.
This item is very seldomly purchased, so it is not carried on stores.
The instructions say it works better with their screws as they are self tapping and are designed to work with their system.
The location of the handle is the biggest difference. K4 the clamping handle is in the back, whereas the k5 the handle is in the front and easily accessible with wide pieces.
If you mean "Does the K5 Jig System come with a detachable pocket hole drill guide like the K3 Jig System", the answer is yes. The drill guide is removable and it also includes one Spacer Block that adjusts the jig for an additional 1/4" material thickness. But if you have a K3 Jig System, you already have a detachable drill guide... unless you just want to upgrade to the K5 system. I have a K5 and I love it.
yes
Does the same as K5. He will love it.
just a cardboard box / with handle
all above