Not sure if anyone addressed this already. I just got the 225i's, and found this thread reading up on mods. Sounded good to me, went off and got some electrical tape but then read that it leaves a crappy residue if you decided to take them off. If you want to avoid that, like I did, try this. I cut one length of tape that would fit all the way around with about a half inch to spare, and then a second piece that would just reach around with no extra. Carefully place the two sticky sides facing each other, and then wrap the strip around the pad using the extra half inch to fasten. For the most part the tacky stuff is only touching tape and not the foam.
For my part I can say I hear a bit more punch with the bass. Not a ton, but you get that slight impact a bit more. I like it. Great idea.