We - my son is the driver and I'm the mechanic - are also driving the DJC axles, and we are driving modified on carpet. We allways use the spool in the front.
We also have the same experience than others, when switching to DJC axles: better cornering. Allmost over-cornering. We have tried several things to avoid this over-cornering and find, that adjusting the oil in the rear diff helps a lot. Earlier we used 800 cst - now 1200 cst or thicker.
Also reducing the droop in the rear is one thing to play with, if you have too much corner entering.
We don't like to change too much on camber/caster, as sometimes the tyre wear go crazy. Especially LRP CPX tires, which are often used in Europe, don't like too much camber, as they pretty soon will make a heavy groove on the inside.
The Serpent S411 is a car, which has a lot of steering in every part of the corner at every speed. As a newcomer it is pretty hard to deal with, as the car is steering immidately, when you touch yor steeirng wheel at your transmitter. It reacts quickly and therefore for a newcomer a bit too nervous. As an experienced driver it is superb, and often just want you want or need. I never ever worked on a car with that kind of steering.
Some drivers complains over less rear grip. I don't think, the problem is in the rear but in the front. They have a setup on their cars with too much front grip.
Our overall experience is, that with the DJC axles - beside the less chattering - you increase the steering, and you can drive with less steering output on your transmitter.
The need of DJC axles depents on, what you want from the car. The wear of both types of axles are allmost like zero. As I wrote, we drive modified on carpet, and we have no play in the axles at all. Superb quality. Big A with several +
By the way - the delrin outdrives aren't designed for using on carpets. We drive the stock steel ones, and a tip: we have put a foil over the outdrives and then filled some black grease into them to avoid wearing. Works perfect.
Just my experience to the steering of the S411.