BL Savage X project

Ok I think I have made my decision on the battery trays. I am going to use two Losi 8E battery trays. They are pretty cheap at $11.99 a piece, Its going to cost me around $45.00 for the trays and straps. I would go with Mike's trays, but I just can't pay $35 a tray.
Also with the MMM and CC Neu if I gear the truck for around 45mph on 4s will the temps be ok?
And one last Q. does anyone know what the DD's gear ratio is? If someone does please tell me, I would really appreciate it.