Upgraded electronics for the NERF Stryfe foam blaster. Added RFI/EMI filters and changed the wiring. Using new motors Solarobtics RS2 motors available at Pololu and Opencircuit. These are regular 130 size so no shell modification are necessary. Batteries should be rechargeable NiMH 1.2V. Wiring should be 16/18/20 AWG to handle peak currents up to perhaps 2~4A. 

I've seen some people twist the PTC to disable it's function. I strongly recommend against doing this since the component serves as a slow overcurrent protection. It keeps your motors, wiring and batteries from burning out. Instead, improve the wiring thickness and find a higher current PTC.