I use the platinum track in my racecar. Back when the car was streetable I never had an issue with the diff. It occasionally pops when making u turns but that is normal. I would not make hard launches on drag slicks with this diff. The cases are not bullet proof, Griggs racing strongly advised against using drag slicks but said drag radials would be ok, but my car has 1/3 the power you are looking to make so I would be very careful in your case. Autocrossers that run big slicks, ie CP class tend to blow up the cases as well. I think it has to do with the tighter turns and the fact that autocrossers are a little more violent with throttle application than road racers. You're on the right track with the diff cooler, it will definitely extend the life of the unit. At some point I'd like to install one in my car. Change the oil regularly if you race. I change my oil every other event per Randy's (DPI owner) recommendation and I use 3 quarts instead of 2. I burned up my unit two seasons ago because I was only running 2 quarts and I didn't change the oil at all during the season. An internal part critical to the unit wore out and it cost me nearly $500 to have Randy rebuild it. I won't be making that mistake again. I use the Joe Gibbs 75/140 when available, but the Redline 75/140 and Royal Purple 75/140 are also recommended by Randy and they can be bought at any decent auto store.
I noticed you are building an LS2. I'm not knocking the motor but I hope you are addressing the oiling issues that motor has. I've seen a few of them blow up at the track in the last couple of years. Good luck with the build sounds like a very quick machine.
NASA AIX Outlaw West Coast