No, use OEM plugs only. The colder heat range means that it isn't going to burn fuel as well under normal driving conditions and this will actually hurt your fuel economy and throttle response. Modern ignition systems are leaps and bounds better than the old days with copper spark plugs and distributors. The durability of the platinum plugs is much higher and the coil packs deliver much more energy. The ignition system is the last thing you need to be worried about upgrading on this car. The turbo is just too small to blow out the spark, especially with the amount of energy these coilpacks create.
You are mixing up a ton of stuff there.
First OEM is original equipment manufacture. In this case NGK is technically oem as they do supply plugs to vw. OEM does not have to be a part anything like stock just by a company who makes stock parts.. What you probably meant was OE which would mean same exact piece as stock but possibly just by the manufacture. Genuine would be identical to the OE but stamped or packaged specific to the manufacture.
This misunderstanding of what OEM means has always annoyed me with people referring to things being OEM+, OEM plus would mean that my BBS LMs and my giant Borg warner turbo along with fixed bucket carbon recaros would qualify.
Platinum just lasts longer, for a plug it does not really perform any better outside of marketing hype. The reason to use them is to get 40K out of a set of plugs not 10K. From my personal experience platinum plugs of even the same heat range have caused misfires and loss in performance in some applications. I don't touch them generally and prefer copper for hte price since i like to change plugs very frequently. The iridium plugs cost a ton but they are sort of the best of both worlds, performance of a copper and reliability of a platinum.
There is also the argument for coppers that you want the cheapest part to be the weak link. I would much rather fry a plug and get a misfire so I get off the throttle then get a misfire from a hole in a piston but my platinum plug is still going strong.
Yes the ignition systems in these cars are great and don't need to be upgraded, and while the plugs are part of the ignition system they have little to do with the strength of the modern system you are referring to. Worn plugs or improperly gapped plugs WILL have issues with the plug not making it across the gap or "blowing out the spark" as even I call it for simplicity at times. A stock turbo car can have problems, it isn't the system that is at fault just the plug.
No 2.0t has a coilpack. They have individual coil on plug, a coil pack is what a later 2.0 8V has or a 12V VR6, a pack of multiple coils in one. These are one coil on each cylinder.. just a coil.
Now back to spark plug temps. Yes heat range is going to affect how a plug works in some ways but not so much how you describe. Heat range is a rating of not how hot the plug gets but how quickly it gets rid of heat. The spark is the same temperature, how hot the plug is before it fires again is what changes. The reason you go to a colder plug is to prevent the hot plug from causing pre-ignition. There is no performance benefit of a colder plug outright. The only reason it may be responsible for more power is because you can run more boost without worrying bout pre-ignition from a plug staying too hot, basically the plug didn't make the power the boost did. A hotter or colder plug won't allow you to run more timing, again the temperature has to do with how quickly the plug stays after it is fired, a colder plug won't let you run more advance.
The issue some people see with a cold plug in an application that you do not need it is during cold start and warmup. Once the car is warmed up you should see no difference in performance, judging fuel economy by cold start is also kind of silly because it's crap regardless. The hotter plugs just help warm up the mixture as a whole when there is no heat in the cylinders. Once the car has been running a few minutes none of that will matter in regards to how the car operates.
none of this matters though since those are just iridium versions of a stock replacement plug with the same heat range.
