Early SL/104 was dist ignition and fuel distribtor EHA systems.
C class was 2.8 displacement.
E class was HFM/SFI [ actually started in '93/300E.. but known as E320 in 94/95 chassis 124.032]
Then the later SL/104 went to Motronic management , but still the same DIS/ MAF controlled engine.
The main changes were engine management... C and SL/S class went to OBD2 Digital format in '94, while the E class remained OBD1 [ Flash Analog DM code system] thru '95.
All "96 and on were then Motronic w/OBD2 .
The S class 140 chassis was actually the last production run w/104..
One thing that would be cool about having a 104 HFM/SFI from an E320
as a power plant for a 113 is it would come with the engine management Flash Code Analog Diagnostics module [DM] with the built-in LED/SW code retrieval system ...so you could access any fuel/ignition management diagnostics of your engine with the push of a button for code retrieval..Now, THAT would be cool..
This is just fancy pants tech talk, as I like the MFI system just fine , now that I finally know how to tweak it...
..but , just for the sake of engine tech talk, here is the DM diagnostics that were available with the 104 engine management format that we use over at Mercedesshop Forum to aid members in SFI electronic diagnostics.....quite a change from our diagnostics over here, but just as interesting..sometimes more so..
http://www.mercedesshop.com/shopforum/showthread.php3?t=107630