Well, I have a full APR short shifter kit, APR metal bracket, Solid bushings, ECS CDV, clutch stop and Clutch spring removed. To me all of the above mods are a must. Some people are only after certain mods, such as cleaner/more precise shifts, shorter shifts, faster shifts, etc... I wanted them all, so here are my observations and a first hand experience.
The list:
1- Short shifter: will shorten shifts (some more than others). Depending on which one you get you may need an extra effort to shift. OEM RS3 shifter is almost identical to stock (effort wise), APR is second best, Diesel Geek is the worst.
2- Solid bushings: If you want precise, crisp shifts this is THE mod you want. This mod will clean up all the sloppiness, so no more money shifts.
3- CDV: If you like to speed shift and/or track your car and would like keep your stock clutch a little longer, this mod will help you a lot. You can also remove a yellow orifice from the OE CDV which will be as close to ECS as one can get. I came up with an idea of how to remove the orifice without removing CDV but I still strongly recommend bleeding it afterwards. ECS on the other hand has a one way valve which makes bleeding super easy and a one person job.
4- Metal bracket: Won't do much, but since I was in there already I installed it too.
5- Clutch stop: Will eliminate dead clutch pedal travel and will make your shifts smoother, faster and much more enjoyable.
6- Clutch pedal spring removal: Will further help with engaging clutch faster during speed shifts.
I haven't tried it yet but I am toying with an idea of adding a weighted shift knob, unfortunately so far I haven't found the one I really like. At some point I'll grow a pair and open up my OE knob to see if I can somehow add more weight (pieceIMG_1795.PNG.png of lead) to further reduce shifting efforts, not that I am complaining