Hardware Upgrades on Unibody Macbook

Hi everybody,

I just installed ubuntu on a macbook pro, late 2011 (unibody, I believe). Although the system is working fine, it is a little slow, and I would like to install a new CPU - and maybe some other stuff.

Are there any limits or restrictions on this type of work? Or can I proceed to switch out hardware as I would with a macbook that was ruing OS X?

Also, if anyone has suggestions on specific types or models of hardware, that would be appreciated.

Thanks!