I had all the 'bling' parts on my Pro 4 and I have to say the only parts that I have put on my cyclone are Aluminium Rear Hubs, Aluminium Front C-Hubs and the Carbon Bumber Brace.
When using the rear hubs everything runs smoother and when using the Front hubs you get less slop (not that ther is much!).
However the small gains from these are offset by the gain in weight. However I think it is worth it with the car being so under weight anyway!
The Knuckle Arms are just not worth it though. There is more weight for your servo to turn. The square versions bend really easily and the Jet ones dont fir the bearings very well.
So in my opinion if you want bling go for the Hubs and forget the Knuckle arms!