Spark plug Bosch or OEM Mazda

Update: went Bosch for the plugs and ngk for the coils, the manufacturer plugs and coils were still in as if no one has touched them since the car was bought, I’m the third owner I believe. Each spark plug was toasted, easily double the recommended gap, and once I put the first two coils in (pulled code P0300, P0301,P0302) the problem entirely went away (coughing and sputtering exhaust, slow to accelerate, car shaking between 20-40 mph, rough starts) so I knew it was a go ahead for the rest of the coils. Feels like a whole new car all around, I can tell the engine is thanking me by what she’s putting out now ????

The best plug I found for a shovel is a Bosch Platinum WR8DP.

I always had issues when I used any plugs other than Bosch Iridium or Platinum. You can even try Bosch copper plugs if you find the right heat and size. They're usually cheaper and better, but don't last very long... like 10k miles.

So the new set of plugs arrived, so switched out them along with new wires, since two broke during work (Magneti Marelli) and since I already tested and bought a new coil pack basically the whole ignition system's now revamped.

So far after more than two hours of driving, no problems, but Im really careful since I dont wan to find out Im wrong, but it feels ok.

The old plugs where NGK, and after pulling them, their resistance measured on average about 4 kohms.

I kept the previous set, which where Beru's and they measured ~1.4 kohms.

The new set is Bosch, and Im going to stay away from NGKs since I drive a little bit sporty, lasted less than two years, and (I think) 20'000 km.

Bosh Double Iridium is the best value. AC Delco as well as the NGK only have an iridium electrode. The Bosh plugs have iridium laser welded to the ground electrode as well. The advantage is that it stays cleaner when it gets up to temperature and will have virtually no wear. Don't get Autolite. Their plugs are almost always out of spec. Out of the box you can ohm them out and 1 of the 4 is guaranteed to be out of spec.

So far we have; Changed to new spark plug wires, distributor cap and rotor and the distributor is not leaking oil, tried two different sets of spark plugs Bosch F6DTC and NGK/RIDIUM BKR6EIX.

I ran them for awhile in my Passat VR6.They did decent.Burned really well actually. I think when I was running them I only got about 23 MPG.

Bosch platinum are trash.

I’ve heard bad things from mechanics about Bosch, specifically Bosch platinum.

the plugs are brand new Bosch Double Platinum.... so then I went out, put them back in and was still a biotch to start....