These should perhaps be called, "Not a great head comb suite."
I just ruined a $250 USD donor's heads doing a head swap on a ST2000DM001. What happened was, the ST3-3 (2) comb would not fit because the pivot pin was just too tight a fit, causing it to break off. I decided to use my Level 1 combs (#123) as an alternative and they worked fine.
When I powered up the drive, there was a loud clunk and spin-down. I opened the drive, removed and examined the heads and that's when I found the broken-off pivot pin stuck in the hole between the top two actuator arms. By being there, it blocked the heads from rotating over the platters. I pushed it out and re-mounted the heads but somewhere during the process or removal and re-installation, I managed to damage head #1. If that pin had not been stuck in there, there would not have been a problem; everything else went smoothly. (I even practiced a head swap on a ST3000DM001 beforehand, and the HDDScan read speeds afterwards were better than originally, as often is the case.)
All this just to caution everyone using DFL's head combs suite # 2: be very careful that you don't break off the pivot pin, and if you do, be sure to locate and remove it before proceeding.
I've offered to refund the customer's pre-payment so she can take the case elsewhere, and she just replied she will take it and ask Seagate what they can do for her. Not a great day!