the engines should not rattle; the vanos is meant to be noisy for like a few seconds then shut up, but if it its noisy for like 1 minute then there might be something more sinister going on such as Vanos

what sort of noise is it? camshaft type noise or bottom end?

edit: The last evo i heard was noisy was purly down to the oil which was used; it was cheap nasty shit and hadnt been serviced for a while, a quick engine flush and correct decent oil and it was quite as a mouse