I do not recommend this, it changes the parameters of the subwoofer. I bought some infinitys that had foam on one and not the other from a friend doing that and you could clearly tell which one had the foam on it just by watching the excursion.
Lol, are you serious?
THe MMs of the driver will probably higher then 200g and adding about 0.5g of foam won't change the parameters that much.
Something else was wrong with the driver or you used a LOT .
Completely serious, there wasn't much on the cone either just two small chunks one for each side. I sold the subs to a friend and they're still slamming to this day, and to this day you can still see which one has foam on it and which one doesn't. I'm just telling you from experience, you can throw numbers around all you want but at the end of the day it will change parameters...maybe not much as you said but they will still change, and side by side its noticeable.