Had some cold starts lately that motor struggled slightly to turn over, which led me to look at the plugs.

In doing that, I noticed the 3rd of 4 coil packs, looks really new, while the other 3 look like originals.
I've read you should replace them all at once? should I just buy 4 and start from scratch, the right way, or is the replacement of just one an ok thing to do?

 

I'd do 4 if it was me. How much are you going to think about it if you only do 3? And will you remember which one needs replacement earlier than the rest?

 

Well yeah, IF I replaced them, I would do all 4, maybe I should have posed the question better. I've got no issues, outside of a couple cold hard starts the last few mornings, but I am pretty nitpicky and when I noticed ONE new coil-made me wonder 'why didnt you replace all 4' to the original owner haha, he had all of his maintenance done at the MINI dealer haha.
I guess the better question, do I NEED to replace all 4? if theres no issues and leaving it with the 3 old and 1 new, will it CAUSE issues.

And, if I did buy them, there are all 4 DELCO coil packs, I see there is a 'genuine BMW'...whats the feeling on that?

 

I have 4 oem's from my N18 2016 that have 30k on them if you want them, ha. I put in Bavarian Motorsport coils in from ECS Tuning.

 

hahaha, I was just looking at those and got suckered on the more torque and better fuel MPG haha.

 

Just bought my 2012 MCS All4 and decided to replace all 4 coils and 4 spark plugs. Glad I did. After a week or so I changed the air intake filter. I thought my gas mileage would improve but still at 23.6 mpg. Still though, the performance has improved. I too went to ECS tuning and bought the kit.