all honesty,the thrust assembly should work very well and resist bearing destruction under side impact.if you use a new flanged bearing and dont hit anything,you will have the same end result with no improvement in diff action.you will still need to rebuild your diff if you want to be competitive at a high level with either setup being that the lube on the diff balls will spin out off the balls in the spur making it necesary to rebuild a diff quite often.the added security you get from not having to carry extra flanged bearings with you for when you hit a wall is nice.so,in a nut shell,for the application,an actual thrust bearing is the correct piece to use for the job,it is designed to withstand side load.does it make the diff smoother or work better if you have exact same conditions?(new flanged bearing vs. a thrust) no it will not.i think the added security and peace of mind makes it worth it.i personally have had the same flanged bearing in my diff for 6 months with no problems.if i take a good side shot to the rear end,i can say goodnight to that bearing.