I notice that Paradise now has 4 inch pads beside the 6.5 inch pads I have. Is there a difference in how they work? I know the colors probably line up with the density but in reading something else it seems that the smaller pads might be slightly more aggressive - no? Also, they will work with a Porter Cable DA right?

 

I've been using the smaller pads now for over a year and they work great for those tight areas. Like the bumper, A-Pillars, swoopy area by the head lights and, since I have a vert, the roof above the windshield.
I highly recommend them. You would need a smaller backing plate and you need to remember that since the pad is smaller the pressure is more focused so keep it moving.

 

Used the four inch pads for the first time this week. LOVE them. My only regret is not getting a white one. Getting one as soon as I get back from MOTD though.

 

Yep - used mine the first time last weekend also - ditto what Chuck and Chris said - I got an orange and a white - used with Cut+Swirl and Amigo, respectively - with great results. Also very good for spot touch up work - I had PDR'd a ding out of my door - paint looked fine, but after polishing and waxing I noticed there were some fine scratches that came along with it. So I had to wet-sand a small area (a couple inches square), then polish that spot back out and re-wax it. The small pads were perfect for that!