Good place to get OEM front ends??

well, i am considering changing up my front end once again. This time to an 03-06 version. Where is a good place to get one at? Also for anyone who has done this, is there any mods  I have to do or is this just a simple bolt on? I have a 01 GMC sierra

sorry about the repost. I didn't see the topic already about this until it was too late and i dont know how to delete post anymore