Your setup looks pretty good! May I suggest that you use some velcro elsewhere besides the battery straps to help hold the batteries in? If the mud guards flex, it could allow the battery(s) to eject.
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz
MM: I can see I'm going to have a similar problem with my buggy. I know I'll need the space over the mudguards and too think they are too liable to break under the weight. I was thinking of making a seperate battery platform (CF maybe?) that would be mounted to the metal chassis with 3/16-1/4" spacers. That should allow the batts to clear the nibs (where the guards are screwed to the chassis) and to keep the weight off the plastic guards.