D8T battery tray
 

Would the d8t tray fit the traxxas 5626 esc holder?
Description says nothing, but i presume yes since the separate tray is the same as the tray that comes with the kit, right?

Correct. The D8, Losi 8, Losi ten T, Inferno GT2, and Mugen MBX6 and MBX6T trays all accomodate the RX8 directly and the MMM with the Traxxas holder. :)

if i cut the motor shaft will i have enough clearance to use the stock radio tray with your motor mount, cutting between the brake servo and front box?

Probably not, I used a motor plate that attaches to the rear of the diff mount, which puts it farther back than an integrated diff/motor mount, and I barely have room for pinion with stock radio (receiver battery) box.

It is possible to use the stock tray(most anything is possible), but much less ideal.