When I raced mardaves which were tightly controlled - I water dipped running reverse, cleaned and lubed the bushings and bought the best 4-cell packs I could and charged them at the absolute max my charger would do, 5 amps I think. They were GP's so I survived unscathed
but that's what you have to do to compete in stock, get every last bit out. What I did wasn't cheating - my car was no faster than anyone elses in a straight line but I won the club championship because I carried speed through the corners on a well-overgeared motor.
And just incase Terry is reading, yes, I ran the ABS shell and I had all the windows cut out and steel mesh to make it look scale. Because I like scale-looking stuff.
It might be a common paranoia among stock racers - certainly everyone 'thinks' others are cheating and by talking to people it sounds like yes they are, at least those who want to win by any means and be 'more equal'