IMO, anything that keeps the chassis stiffer allows the suspension to do its job properly. However, everything I keep reading for RC car tuning suggests that there are times when chassis flex increases traction. This is 100% contrary to full scale chassis tuning, though.

As for the connectors, IMO, the EC5 solder holds the wire much more securely since the entire cup is filled with solder and secures the wire in a full circle instead of securing the wire along one side, like the Dean's. I haven't had any problems with them coming unplugged, but I have not been using them that long. I'd likely replace the connector shell if I had that happen to me to see if that fixed it. If not, probably just replace the entire connector.

I hope that they don't give me problems. I just ordered like $35 worth of EC5 connectors!!!