do I understand m103 vs m104?
 

OK, I'm still researching which w124 to buy - '90 through '95. If I understand right, The bottom ends of the motors in these cars is the same, but the heads are different. (sohc/dohc) If I get a '90-92, 300E, it's the old motor and if I get a 93-95, it's the new.

But the m103's also had a distributor and rotor while the m104 had ignition electronics integrated with the fuel injection system. (and, if I understand right, a different fuel injection system).

Since this stuff is all at least 11 years old, I'm wondering which of these injection/ignition systems has proven to be the most reliable and/or the cheapest to maintain. I haven't heard too many negative things about either of these systems. It seems the later stuff is superior, as long as it's durable. I tend to think that simpler is less failure-prone, but, head gasket issues aside, the feedback I'm getting is that the m104 is regarded as equally durable even though it's more complicated.

I'm looking at cars with around 100k miles...I'm bound to be looking at future repairs, and, if I can set a course now to have the motor that is less costly to maintain, I don't think I'll regret it, on the other hand, I think I'd probably enjoy the extra power of the m104 cars, and that motor also has it's share of fans - not to mention the other improvements, like the headlights, etc. on the newer cars.

I must say, though, I do prefer the grille before they inset it into the hood.

Any opinions?

I think you've pretty much got it already. It's a tradeoff between simplicity and sophistication. You're not going to wrong with either but assuming it's had a wiring harness and head gasket I would lean toward the 104 - better performance and a somewhat longer lasting top end.

I'm on record for the M104. It was used until 1999 on the S320.

It's a great engine, smooth as silk, reliable, and durable.

I have heard many times over that people prefer the M103 for reliability, since the M104 apparently suffers from head gasket and wiring harness issues. I agree with you that I like the look of the old grill more. On the other hand, I like the new style hood and new style headlights a lot.
Since you are considering the purchase of a car that is probably going to fall in the range of 1988-1995 and has around 100k miles on the clock, I would have to say that the most important thing to look for is service history and the condition of the car more than anything else. If the car is older and has been well looked after it will probably serve you better than a new one with no history.
Look at the amount of wear on the tires and the brand. I have noticed that Michelin tire owners seem to look after their cars better than a Korean no-name...to me it looks like the owner was cheap or couldn't afford to maintain the car. Then again a car with brand new Korean no-name tires is better than that a car with worn out tires ;)

Good Luck!

If the 103 has it's share of top-end problems, then a car with 100k on it is looking at some work involving pulling the head no matter which way I go. Hopefully, I'll find one where the wiring harness and the gasket are done already.

That's why I'm thinking about all the other changes surrounding the m103/m104 difference. I don't want to get into a car loaded with any more pieces of disposable electronics than I need to. However, if the technology has a reputation for being reliable, I feel safer.

Another old benz is kind of a long-term commitment for me. As soon as I start putting money into it, I will quickly outspend what, say for instance, an insurance company will give me if it gets totaled. When I start writing those $1500 checks to my mechanic, I want to feel like I've got my money in a smart investment. Not to get too far off track, but that's why I'm getting another MB. Lexus may be, arguably a "better" car, but not one you can form a "relationship" with. I had a Toyota once, that cost me less per mile than any other car, but on the rare occasions I did spend any money on it, it felt like a waste. When I spent money on my '83 300d, it never felt wrong. It's like buying the $80 bottle of wine with your dinner...not necessarily the best use of your paycheck, but more of an investment in how you want to live.

But seriously, nobody has problems with the electronics? - Jim

If you're in for the long haul keep in mind that coupes and convertibles hold a stronger value so if you dump $5000 along the way, a sedan will swallow it whole like it never happened on the resale end of the stick.

To answer your question, I haven't had any electronic problems as of yet so I really don't have anything to go by.

aside from having more top-end power, the M104 has a better torque curve than the M103

the 94-95 W124s also had a better transmission, that started from 1st gear, and had smoother gearchanges. Overall topend gearing is also higher on these cars, for more relaxed highway cruising.

the 94-95 W124s also had better headlamps than the earlier cars, so you don't really need to convert to Euro-beams.

one other important factor is that the newer W124s had dual airbags.

Having owned both engines, I would definitely go with the M104 (IF the wiring harness and head gasket problems have been properly taken care for!).

Much smoother, more economical, better torque, and, believe it or not, easier regular maintenance.

The transmission went to first gear start in 1990 or 1991, and the shift quality is the same, IMO.

All 124.032 cars (1993 300E (3.2) and 1994-1995 E320') got better differential gearing than earlier M103 300E's.

The '94-'95 headlamps look like Euro's, but aren't. They have dot lenses and don't put out more light than '86-'93 headlights. Whether you buy a car with the earlier or late headlights, I would still change to Euro's.

Dual Airbags arrived in 1993 models.

What most have said - M104 is better >
 

but avoid what I did by buying one that has had all the big money items done - head gasket, wire harness, and probably a water pump. It is better if the head gasket has been done recently as the design has gotten better over time. Timing chain cover seal is another oil leaker. In top form the M104 is a smooth and powerful beast, though.

Does the M104 have the electronic throttle?

Why is the transmission better in the M104? I am getting ready to order a new transmission for my 1989 300ce (M103) which has the 722.358 2nd gear start. I could have the 722.358 changed over to a 1st gear start. Should I? I was also told that I could use the 722.368 transmission from a 1994-1995 E320 which has a 1st gear start. No one has really shared any imput on this subject up until now, I have decide to buy the original one. What do you think?

I've driven both 103 and 104 powered cars and must say the 104 is a lovely engine, if a bit noisy. The 103 can feel like quite a lazy engine but smooth, whereas the 104 has tons of oomph for the big heavy 124.

Just to set the record straight, my 300E was a late '91 car and had the first gear start, ASR and dual airbags.

For the record, the 1993 300E (3.2) has the same transmission as '94-'95 E320's.

If it were me, I would buy a transmission with a first gear start. I understand that the only reason for not having first gear start is to improve fuel economy.

Yes it does.