If you have a stick car and you drive it, don't plan on putting in a rear main seal once and forgetting about it- they go through them like dirty socks. The teflon one is better. I don't know that it's ten dollars better, but WTF? It's only $10! You can look at it two ways: either, "Oh my God! It's 100% more expensive!"; or, "after spending $450 on this clutch job, what's another ten bucks?" Your call- I splurged and got the one that sounded cool.