Ignition coil DELPHI or BERU

There are a lot of parts you can trust aftermarket, but electronics are usually better OEM. Denso and Delphi make a lot of OEM Subaru parts. In this case, I believe Delphi is the OEM manufacturer for coil packs, I would try them.

Delphi. BMW started with Bosch and after misfire issues they switched to Delphi (I think in 2011?). Go with Delphi, my old e82 with an n52 had tons of misfires at 40k with Bosch coils and the Delphi’s had no issues.

I had issues with misfires until I replaced the coils with genuine oem. Before that I had all new Delphi 10571 which were not the same and ultimately fixed my misfire issues.

I won't install anything but the Delphi coils.

Don’t get Bosch coils or plugs. Get Delphi coils, they’re the updated design. As for plugs go with NGK

I’ve used both. Didn’t notice any difference. Have Delphi’s right now. Both work great for light and mid tuned setups.

Delphi will be all you need. Delphi are fine even on ST setups running 700+whp. There’s really no need for others.

I had my old OE coilpack off, replaced with the new BERU unit. I had everything put back together, started her up, and she was running okay, but still far from perfect.

Delphi quality has drastically dropped over the past 2 years. We’ve gotten multiple DOA units, and ones that fail within 6 months.

I've replaced 4 of the 6 packs over the last three or so years. All but one actually broke in two when trying to remove them, leaving the bottom half on the spark plug!! I suspect water ingress (not sure how with all that plastic) as the coil packs all showed signs of corrosion.