The engine seems pretty bullet proof. Well maintained is good and honestly, I think your PO would have had to have been an idiot to do something that would affect the lifters. Having the correct oil seems to help a lot of this.
Pulleys will also make raspy sounds intermittently...check belt condition and make sure the tensioners are holding belt flat between pulleys.
And to clean things up generally, Techron--the only additive my car has seen.
As desperate as this sounds, in comedy, 'likes' and 'views,' 'friends,' and 'retweets' really help. If I've ever helped you, please help me by friending, liking, viewing, and retweeting. It makes others think I have a following...it'll take you a minute or less. If you could, I'd really appreciate it!
A recent set--NSFW audio: https://youtu.be/_dcxcZfD6dg
Mangofy your E46!