My bearings were in good shape and tools is all I needed. Hydraulic press, bearing splitter and a puller, etc. RTV, gear oil, break cleaner...
I did mine with the case still in the truck like in the writeup on Marlin Crawler forum. There is also a great video on youtube by OTRAMM with t-case out...
I have 3.11 transfer case gears in mine with 4.88s front/rear. Do not have any regrets and it made noticable difference. It crawles much better it snow with 39" tires. Do not notice any negatives mentioned above. They are a must offroad in my opinion.