frequency response - B&W vs. Monitor Audio


I currently have a pair of B&W 685s and I am considering replacing them with a pair of Monitor Audio BR2s. The MAs freq resp gets down to 42Hz; the B&Ws only get down to 49Hz. Is this an audible difference? I would be getting the MAs through a friend who has access to wholesale prices and I will not be able to audition the MAs.
2nd issue - I am considering high-passing my bookshelfs through an active crossover in a powered sub. This will cut out frequencies below 80Hz before the signal gets to the amp and the bookshelfs. If I do this, does it matter if I upgrade to the MAs? Their high end is 30kHz, the B&Ws high end is only 22kHz. Thanks.
realremo
If you have access to wholesale prices you owe it to yourself to look at the Platinum series. They perform way above there pay grade.
"The MAs freq resp gets down to 42Hz; the B&Ws only get down to 49Hz. Is this an audible difference?"

Those are only numbers, its how they sound that counts. Besides there is very little music below 50hz.

Bob
Bob says...Those are only numbers, its how they sound that counts. Besides there is very little music below 50hz.

I agree with the first sentence.The pitch of the sound is what makes or breaks it.
I disagree with the second sentence to a certain extent.While there may not be a lot of music below 50Hz,what's there is important.The lowest registers of the piano and organ,pipe organs,tubas,etc. fall in this range.Again,the pitch of the sound is very important.Of course these are just my opinions and everyone is entitled to their own.
Also, regarding the high end frequencies, very few folks can hear even up to 20kHz, as far as I know.
Don't forget the room and setup!
Also, when it comes to LF extension of above named, I see no tolerance and certainly no ref to quality of sound.