I want to make my car stronger on both inside and out. I am a pretty heavy racer and off roader with this car, and have just about replaced every bit of the outside. I am now wondering how to make the inside stronger. I know not to replace my spur gear with anything steel, but i was wondering if i replace all the gears in my tranny with steel gears, would that allow me to pop a steel clutch bell and spur on it? Plus the thing that really bugs me about the tranny is the differential gear. It has this plastic case to it and i stripped one of the screws putting it back together so now it leaks and i have to clean out the oil and replace it about every week. So either i want to replace my differential gear casing with metal, or i want to replace my entire tranny with metal so i can upgrade it to an entirely metal gear system. Thoughts, opinions, or help would be greatly appreciated.