I didn't want to drill any holes in the chassis, as it is quite expensive :P
I haven't had any problems with the battery location so far, but i'm still trying different motor and battery locations to see what is best.
I think you may find your handling very much improved with the batteries closer to the centerline of the chassis. an extra 2 holes on each side isn't going to kill the value of the chassis compared to you actually running the chassis for the first time.
I am still testing some different designs, and i went with the "classic" deisgn, with the battery in one side and the motor in the other side of the chassis.
It handles much better, as the design with the motor in the front is pretty nose-heavy.