Yep, the M series Marantz's are kinda rare and deserve to be kept intact as long as they are not tore up. Refoam them! 
BTW, they are 8 inch woofers with a dome cell type tweeter, not the LPF dome like my M10's and elduce's monster M16's. I love my M10's, they are awesome, and they project a soundstage of purity, detail and clarity that even surpasses that of their bigger siblings, the HD880, DS920, DS940 and HD88. The only comparable ones are elduce's M16's M16 is a very appropriate model # since there is a machine gun called M-16, heheheh!
The M Series were Ed May's last line before his untimely death in 1980. Marantz did have an "M" series in the very early 70's, but those were a spin-off from the Imperial Series, and the M was suffixed after the number. The M's I'm referring to were only made in 1980 and the letter is prefixed before the number. The M2/10/16 took over after production of the HD/DS ceased in 1980. The production run of the M2/10/16 was so short because Ed died that same year, and upon his death, production ceased, making them perhaps the rarest Marantz speakers made. My M10's I found were a complete stroke of pure luck. I had intended to use them for parts, but upon seeing them, all they needed were surrounds and a good scrubbing. Upon finding out how rare these were, I just could not bring myself to scrap them. Once I listened to them, that made it even more apparent to leave them be. They project a huge soundstage with beautiful/dynamic imaging due to them being mirrored. They are on a VERY short list of my favorite speakers of all time.
hehehe here I am!
