The chassis brace connecting all the diffs was custom. I've found that the normal F/R braces that angle down to the chassis still allows flex. With the brace I made, there is MUCH less flex. The stock rear brace on the GTP attaches to the radio box. I imagine some type of custom brace will need to be done so it is on the other side of the driveshaft (otherwise would interfere with the motor). Pic showing the crappy rear brace layout:
