I have both the JHM short shifter on a spare RS4 01E and a UK made shifter fitted in my car. They both look much the same and I haven't measured up for minor differences but the UK shifter is spot on. The OE setup is a fairly light clutch and a long throw which match in feel. My fitted box has the 1-2 hesitation with wear in the synchro and shift collar. Contrary to popular belief, fitting the short shifter actually improved the shift to where the 1-2 shift is actually quite OK as is. A reason I haven't prioritized a box swap yet.
Some years ago I added a plus 15 clutch and short shifter and the clutch is markedly heavier and the shift very short. You can certainly get the shift adjusted to a perfect alignment and the pair just complement each other in feel using a stock knob. Personally can't see the benefit in the weighted knobs with a throw of 2-3 inches.
I wonder if the short throw makes it feel notchy. I'd call mine firm but there is absolutely no interference between neutral and in gear and that's in an old box. Just ''click". That said, it took some time fiddling to get the alignment perfect. Made up a tool as a spacer gauge. In part you can tell when you are in the alignment ball park as you can get reverse every single time with no issues.
My fitted 01E box is the early linkage RS4 version and the UK shifter came in different versions for that one and another for the later linkages. The spare box has every bit JHM made thrown at it, in and out. I haven't yet fitted it but the PO spend a mint getting a race build and then wrote off the car, but he reported it as a sweet shifter.
JHM exterior bits
and the UK shifter