Rebuild 727 with shift kit ?'s

So, I just pulled my 727 Sunday morning because the front seal was leaking. Since it is out I wanted to do some mods to it. i want to have somebody to rebuild my transmission with these

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320766785484 over haul kit.

and

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=8019404661
Shift Kit

There is nothing wrong with my trans except the leak whick is in the overhaul kit. Would this make my tanny a hard shifting bat out of hell?
And would it be possible to do it myself?