I agree with particleman's advice ! please do check according to what he has said !!
What I would like to add here is,If you have tried all other options and have found little success (after trying the above suggestions aswell) ! One trick might just work for you,that is the DIY mod trick !
What you can do is,add some extra damping material to already existing !! you can use polyfill or glasswool based on your choice and availability !! This for sure will eat the additional bass and make it more sober or tight !! This has to be done inside the speakers ! so one you should be ready for removing the drivers and such ! second there's shouldn't be any warrenty issues from dealer !!! so please check for this before proceeding with this method !!
Let me know if you require more info or any additional suggestions regarding this !!
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 !!