Respraying, guitar tanning and pickguards

[SeanTracey]

Alright guys, I have a few questions:

Is it possible to have a guitar soundboard re-finished or resprayed for whatever the reason, be it to replace a worn finish or just if you fancy a different shade? Would it make a difference to the sound of the guitar, whether for better or worse?

Say I wanted to replace a tortoiseshell pickguard with a clear one on a year-old guitar; will there be much of a tan line left underneath the original pickguard since it's so young, and then would it be worth letting the tan line 'even out' before putting a clear guard back on?