I have a dyno appointment on Monday, June 9th and am worried that my O2's may be a little sluggish, so I am planning on replacing them.

I have heard before that there are better O2's than others for some reason. Does anyone know which ones are better than the others?

These are going on a 87' P1SC'd 5.0L w/an A9L computer. I have long tubes as well if that makes a difference (I know it does for the heat to the O2's).

Can anyone offer me some advise? Thank you in advance!