OK...
I take it you want to share because you started the post (if started for bragging rights only thats cool too, definitely something to brag about), but a number of questions have been asked and left unanswered....eg manifold being run (Stefans runs modded cast iron, which would have it limitations)
It is very impressive on the limited info available.
I presume it is on pump fuel? and naturally aspirated (because if it is on the bottle less impressive in my opinion)
It is has made 44 rwhp than Stefan, so I dare say not only does it make more power but it makes it differently because going a "bigger" cam would be useless cosidering your stated 5100rpm over the line. (see Stefan graph below, impressive power curve at peak RPM)
I don't recall Stefan weight, but going by your quoted weight with driver wouldn't be "that" significant a difference comparing to other cars/XY's I have seen on the scales.
So I have to presume "again" the differences being in suspension set up? because we have both mentioned the different tyres being used.
cheers.