All about the Roland Jupiter-series

I read some threads a while back that said some earlier MKS80's had 
warmer and a bit phater sounds than later units and some units teneded 
to be unreliable.

I have jupiter 8 one of the earlier models that does tend to go out of 
tune some times but from what I heard sounds a lot phatter than later 
models which fixed this kinda detuning.  I think it was based on DAC's, 
8 bit vs 12 bit thus later models having 12bit.

Anyhow does anyone know about what serial number to look for later vs 
earlier models related to my TOPIC., including Jupiter 8's

Myabe a link to site that can explain better?