wheel spacers: good or bad? safe or unsafe?

[sixtons]

forgive me if there is an easier/better way to link these posts, but this topic arose from a discussion UROTRASH and i were having in a post called "what size wheel spacers should i use?"

UROTRASH states that spacers are not safe and he would not recommend them. I have heard this others places before as well, but never specifically why. I have also read that, to the contrary, wheel spacers can actually improve performance by lowering center of gravity and extending wheel base.

in true forum style, i would like to open this up to discussion and see what everybody has to say about it.

thanks to all. cheers.

ps - given: you are using quality, rated spacers (i.e. h&r, etc.)
given: you are using proper length bolts (longer to compensate for spacer size)
question: are spacers still unsafe??