i would not buy the 300mm u joints i would just buy good qaulity ujoints like spicer. You have to keep a weak link somewere in your drive train. My experience with heavy duty u joints like longfeild came out very exspencive i kept snapping axls shafts at the ears and yes (even chromoly axles) and could not figure out why untill i had a vetern bring it to light for me. He told me that it does not pay off for trail rigs to have super ujoints for one they have no flex 2 they are not practicle money wise 3 its not like you can just make a trail repair unless you pony up the cash carry spare chromoly axles with ya i know when i spend 800 dollars or more for a set chromoly forged shafts i want to keep them as long as possible. I would much rather spend 25-30 dollars on a spicer brand u joint and do a trail repair then lose out on a 300 dollar inner or outer shaft. That high dollar u joint is gonna look real pretty sitting in the mud with your snapped chromoly shaft wishing that u rather of had a snapped u joint then see your high dollar shaft go down the shitter and then you realize dam i dont have a spare shaft to make it home but if had a spare ujoint in 30 minutes you could be wheelin again instead of having you trail buddy towing you. You dont have to take my word for it but im just giving a little food for thought