Product review (5 stars): Great product at a great price!
Excellent kit!  I tore down and replaced the agitator internals in about 15 minutes on my Whirlpool washer.  It was quick and easy and everything seems to be working great (I'm on my 2nd week of laundry at this point). My clothes are definitely cleaner now that the agitator is working like new.

Be sure to buy some synthetic grease as some of the internals call for it.  I purchased Super Lube 21030 Synthetic Grease for mine and it seems to be just fine.

Also, if you are unsure how to replace this kit, I found plenty of videos on youtube that walked me through it (which is how I was able to complete the project so quickly).