Ehhh, I would still do NRW again, any day of the week. And it is the only cover I'd ever recommend to friends.
If I am not DIYing and the shop messes it up they can take it up with NRW and sort it out between them as to who is going to foot the bill for any mistakes.
EuroPower is a poor option IMO mainly because of the reduced crank-case ventilation performance.
MLT is the only billet option I would go with, if for some reason you have a pile of spare cash and don't like cast aluminum for some reason. Much more on my thoughts regarding all common valve cover solutions can be found here:
BMW S65 valve cover options (mostly inclusive).
My experience described in the post above is with the absolute first round of their valve covers. And as far as I know they have not changed their supply chain, but certainly could have changed other things since then. However that would not have come into play for my set. It just took me years to finally get around to installing them. =/
I want to stress that there were no issues with my NRW covers that the stock units don't also suffer from (minor imperfections in the coating, coating where it doesn't belong, potentially tight holes) and I would recommend NRW covers from the mountain tops if I could climb them all. Yes, they could be better and I will get into that below, but they are certainly the best option IMO when you factor in price. (MLT might have them beat a little if your budget is unlimited.)
I have spoken to Neil Gordon at NRW-Deisgn since installing my covers about two things, but didn't mention this hole threading/depth thing because it seemed
so incredibly minor as not worth even bringing it up.
The things I did bring up are discussed in the thread I linked above, but to summarize:
1q) Please incorporate the spark plug tubes in the casting.
1a) The casting cost a lot of money. No plans to do this.
2q) Please mask-off or otherwise prevent coating the rear-most coil cover pin stand-off to make coil harness grounding better.
2a) No plans. Customer should do this.
Finally, I am likely the most detail-aware person you're ever going to run into. And yah, I found a few things about the NRW covers that weren't perfect and areas for improvement (which is the main reason I made
the linked thread I keep hoping people will read), but I still think they are far and away the best choice and have absolutely no hesitation to enthusiastically recommend them over and over again. Do not go elsewhere unless you're prepared to regret it (except maybe MLT depending on budget).
