Spark plug Bosch or NGK

NGK is prob the best sparkplug for performance, Denzo is a cheaper option but there not as good for performance

If you live some where hot, have a tune, or are hard on the car I would do one colder and get the 2309 instead of the stock 7913.

Any correct sized , heat range and gapped NGK plug will work fine but some will need to be changed more often. BKR6EIX for example is a good choice, it is iridium tipped and not expensive.

Always stick with NGK. However, NGK has different lines from copper, to platinum, and iridium. Iridium is more expensive, but will last longer. Given they're a bit of a PITA to replace, I'd go with these. I've run them in my 2004 WRX the last 8 years.

if the car isn’t stock and has been tuned, you’ll want to follow the recommendations of your tuner/just put NGKs in it.

Car is very picky about spark plugs because it uses the spark plugs as knock sensors, I used basic NGK copper plugs and replaced every 10k. Very easy to do.

Just changed my spark plugs.. went from 031/032 factory NGK1675 gap down to 027/028 gap (based on the feeler leaf gauge). i am here to state beyond shadow of a doubt that 027/028 gap feels way better. The car is smooth.. so smooth in fact that it makes me feel like the CEL is about to come on. In 7 years of ownership, I never felt it as smooth as it feels now. When idling I almost feel as its off.. also at speed!

Just got a Jetta again - 2010 Limited Edition just shy of 100K miles and I've got one problem with it. From a cold start, usually in the morning, the 1st 10-15 seconds run rough before settling down to idle.

Plugs I use Platinum plugs on my tuned 1.8t .I tried using bk7re's 3 or 4 times and each time the car ran like crap. I gapped at 028,tried 030 .The engine made less power up top every time by a difference of 2/3 psi.

Just reporting in after some usage... the NGK 4644 aka BKR7E seems to foul easier than the Autolite plugs I ran previously.