I've recently bought my first 1/12 in about 20 years, a used RC12R5.2 to run on 10.5 blinky. I bought some diff balls and new Kimbrough spurs to freshen up the diff. To my surprise the spurs take 12 balls but Associated sell them in lots of 8... Can anyone recommend alternative diff balls, or are the Associated ones good, but I'll need a few packs?