I am running the Tekno battery tray/straps and it is top notch. But may be it's just me. But I ran my brushless Slayer twice on the local track and I noticed some bend in the center support (it's pretty thin and designed to hold a relatively light fuel tank). See the first set of pictures, you can see how there is a gap between the tray and the middle brace, this is because the middle brace has bent downward slightly. Now I figured if you run a brace across the chassis using the carry handle holes (which are in the right place already) you could add a substantial brace with little effort. I took a 6061 bar of aluminum put a double bend in it, drilled a few holes, made a small spacer and then using the carry handle holes put in two M4 button head screws to hold it to the chassis. I just need to just add a heavy rubber pad under the tray area, clean up the ends and I am done. Actually you could retain the handle by threading the screws into the handle or for a super strong setup just use M4 nuts and discard the handle. Hey Tekno how about making a cool milled anodized brace, and I volunteer to test it for you.
This is the part that appears to be bending
With the tray bolted down front and rear, there is a small gap between the tray and the support on the middle brace.
Now using holes that are already in the chassis, marked by the arrows.
Take a bar of aluminum and put a double bend in it (one to clear the chassis and one to clear the motor brace)
Drill two holes that line up with the carry handle holes, make a small spacer.
Then bolt it down to the chassis, the piece that extends out under the tray can now be padded and will add extra support to the tray.