I've vowed never to buy MIP again. I bought an MIP ball diff for my mini-t a while ago and the outdrives were made of some rediculously soft metal. After 10 minutes running the cups had 'slots' in them where the dogbone cross pin touched. I sent several emails and they never answered any queries regarding this.
To top it off, the drive cups were far from standard so there was no substitute (That I could find) and the rebuild kits only came with ONE cup. So $15 for the diff, then another $20 in rebuild kits for every 10 minutes running I had. I think I figured out their marketing strategy... but instead of making me spend all my money getting new drive cups all the time

I just have vowed to never give my money for what i considered an utterly crap product.