noisy tappets

Hi Folks, I tried looking around the forum for information on this but didn't find anything. My next project on my car is to replace the tappets/lifters on my engine. There are many reasons I would like to do this, the main really comes down to it being a hobby. So please don't use this...

Well it's been 2 days being an A2 owner and... 1. When I start her up from cold she sounds like a deisel for a few seconds then all of a sudden silences to a purrr. Is this normal or do I need some tappets replacing? 2. Once it reaches normal operating temperature and in neutral with my...