I've just installed a Rockford Fostgate T400X2ad amplifier with the Hertz HCX 165 this past weekend. You will have to dremel a clearance hole for the magnet. It works best if you remove the enclosure from the bike to work on it. I made a clearance hole, then used some sheet plastic that can be heat formed. Cut the sheet plastic a 30% larger than the hole, place it on the inside of the enclosure, place the speaker in opening, heat the plastic and then secure the speaker into it's final position. The speaker magnet will form the plastic for you. I also had to mount the Hertz upside down (with the logo at the top) to allow for more room to make the speaker connections.
I can't compare against the 62.11i, but I've listened to a mix of punk rock and metal today. At 70mph with a 3/4 helmet, I can hear clearly with no distortion.