Yes the massive pads and discs are what bring about the biggest improvements in braking, at the cost of pedal feel....and unsprung weight (to a large degree). Leverage, friction, dead mass and physics at play here.
The first cm of pedal travel is dead/soft compared to OEM due to Master Cylinder volume vs caliper volume mismatching. The fix for that is the larger 25mm TTRS Master cylinder (late GTI is 23mm for comparison, early = 22m). 1/2 to 3/4 pedal pressure is significantly more powerful than OEM though, so it's a toss up of subjective pedal feel vs value as to whether the (very expensive) TTRS Master cylinder is worth it or not.
The OEM 7R/GTI PP/Cupra R pads are partitioned in the middle, so not sure what brand the pads pictured are.
All you need to fit them is the carriers, pads and calipers. MK5 back plates and hoses work just fine. Don't get sucked into the braided hose rabbit hole, the difference is minimal to non-existent/placebo. OEM ones are kevlar reinforced and plenty solid enough.