I recently purchased this conversion kit as well. I was lucky enough to have a water logged Razr to experiment on before cracking open my functional phone.
Some tips?
-Buy a plastic pry tool - the one supplied by iSesamo was steel and made small scrapes in the side of the phone chassis.
-Spend the money on the RAZR MAXX Black Internal Metal Chassis PCB Bracket - I used a Dremel drill to shave down my Razr bracket. When you shave down the bracket you need to check to see if your bracket fits back into the phone chassis. I had to check about 4 times, each time you must use the pry tool on the side of you phone, increasing the chance of snapping your bracket or scratching your phone or shorting out your motherboard.
-If you had any accessories for your Razr like I did, Case, HD Dock, Car Dock. Understand that these will no longer fit your Razr Maxx adding to the increase in cost immediately.
-You must have T3 and T5 screw drivers.
-If you don't buy the recommended bracket for $26.95, you must have a Dremel drill or something similar.
-Be VERY careful removing the speaker from the old back bracket, I shoved my flat head screwdriver right through the thin cellophane ruining the speaker all together.
-Use a soldering iron to heat up the plastic pegs securing the flash before removing it.
-Watch this video, all of it. [video=youtube;2GXDQtl1DJY]http://www.youtube.com/watch?v=2GXDQtl1DJY[/video]
The end result was a converted Razr that is slightly heavier, slightly larger, but holds a charge for my entire day with heavy usage. As long as you figure your costs into this conversion and have steady hands to complete it, I would recommend it.