I think the cosmetics went downhill. The 81-85 126 looks styled. The 86-91 126 looks modernized... not modern but modernized. But that's just me.

Differences...

- stereo was improved a little but you have that covered

- factory alarm - both of mine have bad door handle switches. Not worth fixing

- memory seats with power headrests

- telescoping steering wheel

- manual AC recirc button, but on a timer

- central locking from passenger side and trunk (from 85?)

- IMO more comfortable seats in 88-90

- tilt mode in sunroof

- crappy aero headlights but with wipers

- outside temp display

- ABS (from 84?) and airbags (from 85?)

- other things?

You're not missing much.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD