DSLR Mirror Lockup...permanently?

[LAW]

Since I filter modded my 450D and cut the back open for TEC cooling I guess I've passed the point of no return, so I may as well abandon any illusion that this camera will ever take family portraits again and permanently lock the mirror up. Will this throw up any error codes? Am I right in thinking this will only affect the viewing prism, light meter, and autofocus? (None of which I have need for).

Thanks in advance.