Actually, unlike the C220/230, the 280s had a good sound system. They came with an 8 speaker Bose sound system.
I have a 1995 C280 and love it.
Things to look for are the head gasket leak and the wiring harness.
It seems every year got something. I'd say go for 1996 because of standard remote/flip key and newer climate control (though function is really the same, just different setup).
But in 1997 they got the 5 speed auto, driver adaptive.
And then in 1998 they got a make-over and the smart key.
For me, it's been a great car. It's been fun to drive, it handles great. It actually can take a lot more than you think it can. It's got great acceleration, great brakes (last set of brakes lasted 35k miles, not bad for my driving style), and is a nice compromise between luxury and sporty, though considered luxury.
Any other questions?.... I'd love to answer them!
2006 E350 w/ 155k miles (Daily Driver)
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)