Hi,
With all due respect Neo !! what do you mean by damaging speakers by damping

???
Its pretty much clear and evident from Spiro's post that it is due to the room conditions and limited placement options !! also he has very very clearly mentioned that he cannot do much bout it !! hence various solutions are being offered and one happens to be mine !!
If you read clearly I've made it very clear that try all methods and then resort to internal damping !! but even otherwise I being DIY guy myself have done tonnes and tonnes of such mods to various speakers and till date have only managed to improve the sound rather then damage any speakers !! Not to mention have designed and built number of Speakers over the years !! So I know what Am talking bout !!!
I mean forgive me if I sound rude ! but its ridiculous to even think that extra damping will damage the speakers ! if you say it might cause some issues with the sound reproduction or may reduce overall sound quality I may have agreed to certain extent !! but DAMAGE ???? give me a break

!!
On the other hand I agree with you on the other thing you have said !! Spiro do not try to stuff anything from the port !! it is not atall recommend !! at the most what you can do is just buy some round shaped sponge and just insert into the port (only till the end of it,not more)and see how that works ?? if that does the trick then fine !! else try to dampen the speakers from inside I guarantee it will cut the bass !! if you have any doubt as how to go bout it,just ask I'll explain !!
Regards.