Spark plug OEM BMW or OEM Mazda

I just changed the spark plugs for the first time in like 175, 000 miles

use BMW OEM plugs from the dealer. Yes the are expensive but I have never had a problem with misfires and I've put over 100,000 miles on my current E36 and over 150,000 on my first. While they are suppose to work and be interchangeable according to the manufacturer the NKG you buy aftermarket are supposedly different than what you get from BMW

So I decided to I replaced my spark plugs. There was a ton of carbon build up in the first cylinder, and oil on the 2nd, 3rd and 4th spark cylinders, including the spark plugs. It’s running way smoother now but there is still some jerking but it’s not as violent as before.

I had similar problems with mine until I tried stock F80 M3 plugs. Mfg #12120039634KT1. Mine was 07 N54 FBO.

Guy was gunna charge me $720 USD for changing my serp belt and another $550 USD for changing just my spark plugs. That's $20 for the serpantine/drive belt, $150 for the belt tensioner and I think another like $120ish for spark plugs (B58 engine). So in total I saved myself roughly $1,000 just doing it myself.

Rx-8 in 3years just did maintence and ned sparkplugs 0 problems.

I'm pretty sure that modern Mazda's do do this, only not in the situation you're describing. They use it for their stop start system to save having to fit a beefier starter motor and what not, simply inject an extra dose of fuel and fire the spark plug to get the engine going again.

Ours has been pretty reliable, had some issues with odd stalling once which was cured with new plugs/wires/carbon cleaning, rear shocks just went recently.

I did track it extensively, probably 3-4,000 km of track use. The only thing it needs is brake fluid and better pads and you're good to go. My car was flawless for the entire time I had it. It threw a CEL right before I sold it that was solved with a simple spark plug change. It never overheated at the track and it was a lot of fun there and very refined and comfortable for highway travel.