Replacing the spur gear

[littlened]

Firstly, this is an expensive hobby.

I've just had the lazer and some cones out, and somehow managed to get a stone between the pinion and spur, the pinion is fine but the spur now has a damaged tooth which produces a very unhealthy roar.

So, I need to buy a new spur. 10 minutes practicing has just cost me £5!

First time I had the car out I broke one of the standard shocks, they were crap anyway. Second time I took the car out(racing) I broke something on the front that holds the pins in and had to replace it with an alloy one. Now I've damaged a pinion. I've only had the car out three times!

Now I have to order a spur, I'm wondering what the difference between the RTR spur (la206-78) and the SP spur(la206-18) is ?