question about Truecrypt , encrypt my xp and vista

[mantra]

Hi
i have 2 questions about Truecrypt

i would like to encrypt my all hard disk , with xp inside
and my laptop with vista

well my questions are

1)
i start to encrypt my all hard disk with xp , it will be slow because truecrypt will encrypt everything and add a bootloader

well will be my xp fast? or will Truecrypt slow down my pc?

2)
if i want to restore and to de-crypt my xp to the original , does Truecrypt restore everything (xp boot loader too?)

thank you so much