Seems a lot of talk about plug gap and tunes...sure, increased boost and fuel can disturb a plug's arc. I do not see mention of coils. Oem coils are 3.3 ohm and work better with a larger gap because the arc is larger. R8 coils are 5.3 ohm and work better with a tighter gap because the arc is smaller. I use oem @ 0.028" or NGK PFR7B @ 0.028" without issue.
Coil Ohms;
Stock: 3.3 M ohms
5 cylinder coils: 4.75 M ohms
R8's: 5.31 M ohms
Okadas: 6.2 M ohms
What works for one tune, coil, and plug set-up may not be perfect for another. The best one can do is install a new set of plugs when all else is known to be good, drive it somewhat hard for a bit, then remove the plugs and check if there are signs of hot fouling or cold fouling. Also, you want to be sure the LAMBDA is good and fuel is being burnt thoroughly and not too rich or lean.
If you have just tuned for a bigger turbo or simply switched to a more aggressive tune and you notice some shaking or stumbling when you floor it...then you probably need to close the gap a bit if coils are known to be new and you are using oem plugs. PFR7B come with a gap of 0.028" and are a great plug with an aggressive tune and 'mas' boost...so you can use them if you do not want to mess with the gap. I use them when I have boost turned up to over 23 psi. Right now I have all WG preload off and I use oem plugs.
But if you prefer someone to say all of us should do the same because that one way is best...ummm, then stay tuned.