Mendelssohn Srting Octet, op. 20, any suggestion?

The Telarc recording by the Cleveland and Meliora Quartets is very good.

There are several string quartets that stand out from the crowd, with the Emerson String Quartet, and Quatuor Mosaiques being among my favorites. I'm not sure if either of these groups have recorded the Mozart work you mention, but it's worth listening. The Quatuor Mosaiques, by the way, have several wonderful recordings on the Astree label of Mozart and Haydn, featuring fine performances and terrific audio quality.

I too have and like the Telarc recording of this piece, but once you hear and watch it played live you realize how difficult it is to capture the excitement and energy of a performance of the octet on record. I'm hoping others have some recommendations for this work, particularly on vinyl, that can truly convey that energy.

For the LP/Vinyl folks; look for the Academy of St. Martin in the Fields Chamber Ensemble; Phillips LP# 9500 616; There is a CD reissue also of this recording; Phillips CD# 420 400-2

There is also an "I Musici" LP from 1966 which is excellent.

I agree the Telarc Cleveland/Meliora CD recording is very good.

Another decent choice on Sony is "Musician's from Marlboro" Sony Classical CD# SMK 46251