Mods for MS-20 /CS-15?????!!!!!

[Zsolt Homlokos]

i am always wondering how difficult it would be to make
the MS-20 have an LFO with a wider range ,to get up into audio
range?(same with the Roland SH-synths)
or the Filter of the CS-15 selfoscillating (i dont mean patching the out
into ext.IN)
i wonder why the manufacturers didnt implent it from  the beginning ?
it would make the synths more interesting,( not that, they arent already
fantastic synthesizers :)  BUT they would be even better.

though my technical knowledge is quite limited i would appreciate some
advice.
thanks
Zsolt