There's a fairly lively discussion on this subject here http://www.audi-sport.net/vb/showthread.php?t=34050

Personally I'm with falcompsx on this one.

 

Thanks for the replies...the difference caused by the FSI makes sense to me as well.

 

Not sure if this will help - the rattling that you hear during start-up may be the timing chain slack, the tensioner is controlled by oil pressure, until the engine revs and warms up this sound is present on my engine. The mechanics mentioned this is normal. Any comments.

 

Hey, that would make sense. I guess the chain vibrates a lot until it is tightened. I started my car the other day and there was this mad rattling noise for about two seconds - kinda like the valve ticking that tends to appear until oil pressure builds up, just a lot louder and more intense.

I was also worried about the diesely engine noise until I learned that all the FSI's make that noise due to the high fuel injector pressure.