Will a sidekick plan work in a nexus one?

Will I be able to see all the features, such as programs, if I open a string One of Google and a buddy plan from T-Mobile? Not one of the two men suits you answer my question. A job aid will be prepaid, and all the features.
This is insane… You do know that you can buy a Nexus phone by upgraded your contract with tmobile, right?…If you have tmobile and the sidekick plan doesn’t, then you just change the plan…What’s the point of unlocking the phone?
Every Nexus One is unlocked, you do not need anything to unlock Nexus One, all apps are available for it and Google update Nexus One when there is new feature