I do use the tamiya aluminium toe-in rear hubs (i thought they are 2.5°), it did improve the cars handling.
With the last modification that i got from Qatmix's idea makes the car a bit faster cause of the rear grip advantage.

In my last post i refered to a wrong laptime of the other guy.
I've mentioned 23.5s but it was 22.4s with Ride 32 tires while i was just using tamiya medium narrow radial tires with a lot of wear.
Cause of all the changes i'm still 0.6seconds faster and still searching for some extra speed
I've got a new set of tires glued on a set of wheels with some offset to get the maxiumum width out of this chassis, that will make the car more stable when the car goes into corners and give the car more corner speed.
I will do some more testing.