Snapped the normal Lvl 5s with 50 miles and then they upgraded me to pros for free. So far they have held up. You can buy a mess load of stock ones for the price of them.
I broke a stock one so I went with the level 5 Driveshaft Shop ones. So far no issues. They are pricey. I could have bought a stock replacement for about 300. Like I said no problems but I haven't been to the track yet. If I would have had traction control I probably wouldn't have broke the stock one. The rear of car left the ground still accelerating and hit the ground and snap. The longer wheel studs look cool and tells everyone you don't have stock axels lol. I also had a steeda stop the hop kit installed. It still hops a little but sticky tires will help with that. Drive shaft pro does not have these things laying around they make them per order. So I had to wait a little while, only 2 days.
Imo those axles are a waste of money. Most of the time wheel hop breaks axles so you need to do a bushing kit and the hop will stop. I have a full FTBR kit in my car now and it has never hopped since. If the tires spin it just stays planted and goes. I have only broke 1 axle in the 12 yrs I've had my car. And that was after 18 passes in one day at the track on slicks and totally stock irs. Use the money for the axles on a good delrin bushing kit. My car also feels like it's on rails now in the rear.