Hi Silone,
No don't mind the questions

I would like to try narrowing the rear section of the chassis to possibly induce a little more flex, hopefully allowing a little more weight transfer over the rear axle.
Also I would like try lowering the electronics by opening up 1mm deep pockets around the esc,motor and battery. I don't own any Ezrun ESC's anymore so couldn't tell you if 1mm is enough of a difference to allow them to fit! What dept are they? I would also like to consider weight balance if i do this as it could be aid in getting the correct balance without adding so much weight.
Another option worth considering is a slightly extended wheel base as there is a few mm allowance to meet maximum size for the category. This may be a different method to stabilize the car in high speed sections (which in my opinion has always been the GTB's main problem as the font end is really quite pointy/aggressive and the rear end is a bit loose as standard).
Will keep you all informed.
If there are any racers out there who may be interested in beta testing at a reduced purchase cost please get in contact