R129 Daily?

Hey guys, I've been driving an 03 Volvo S60 (base with the 5-speed) for a couple of years now at around 35,000 miles a year and it's getting far enough along in its life that I'm starting to lose a little trust. I'm also just getting a bit bored. I drive across the Causeway to New Orleans every day for school so 50 miles of my 85 mile commute is 65mph and straight as an arrow, so the comfort of the Volvo has been appreciated and I'm not sure I could endure much worse. 
 

My first car was a 95 E300 Diesel with over 300k miles and it was still amazingly solid, so I have a bit of a soft spot for that era of Mercedes. I found this https://www.facebook.com/marketplace/item/364531884442534/ 

(it's a 1991 300SL 5-speed with 87k miles)

and it's really got my attention. A manual is a must for me, a convertible is nice for a couple months, and I imagine it'll be quite comfy. So what do I need to look out for? Is this as cool as I think it is? Does anyone have any experience with putting a lot of miles on an R129? I'm definitely not afraid of continually tinkering but I'd rather not have to worry about anything being too much of an undertaking or prohibitively expensive. Let's see what the hive says. 

IIRC, that era of Mercedes was one of the most over-engineered, over-built cars ever built. If you avoid the limited-run stuff like V12 AMG models, they are near indestructible.  My guess is that electronic stuff is the biggest problem, and expensive to fix.

R129s share much of their platform with the w124 and have commensurate longevity and issues, plus the complexity of the top mechanism that is all automatic.  The manual transmission parts have to be quite rare if there are any issues.  The M104 is well understood overall, and likely due for a head gasket soon at that mileage if not done yet, but should then be good for another 100k.  Like most Mercedes other than from 96-05 ish, they will last a long time if you give them good maintenance, which is more than a Toyota. 

I’ve never seen the 6 cylinder version here.  My wife used to want a 450 SL, but I think that urge passed.  

Nothing to add here, except a week or so ago, one of the salesman at my work came back into the shop spitting and swearing and trying to find a rag. Apparently, a customer was trying to trade in an R129 SL500 convertible on a new Chevy truck and the salesman was making sure everything worked before accepting it as a trade-in. He went to run the top down and it blew hydraulic fluid all over his expensive shirt and pants. Needless to say, they did not buy that car on trade-in. I was kinda hoping they would and then see if sales would sell it to me cheap to do dumb things with. X-Prepared SL500 speedster anyone?

I think that car is amazing, won't really lose value and you will like it. Fast enough to be some kind of fun, slightly more comfortable than the Volvo, and easyish to work on when needed. For the record i have an R129 I havent put many miles on and have spent a LOT of time in 03 Volvos (lol).  

If you don't want the top issues then find a hardtop (fairly common, have seen as low as $300) and leave the soft top down for the rest of time until sale. 

Check for hydraulic oil traces on the back of the interior rear view mirror before trying the top mechanism. The windshield header is full of hydraulic cylinders and hoses for the top latch mechanism. Not expensive or hard to fix, but nasty if a surprise failure, see above post!

The roof mechanism on R129s is a PITA to fix when the expensive hydraulic cylinders start leaking. And they all do sooner or later.

Other than that it's mostly standard Mercedes fare, including the compostable wiring looms in the mid-nineties models that self-compost way too soon.

In reply to BoxheadTim :

I had to replace the looms on my E300 but I've read the 6-cylinder SL's don't have that issue, can anyone confirm? And does anyone know the approximate lifespan of rebuilt hydraulic cylinders? Thanks for the input so far. 

I looked into one of these in manual when a local example came up at a good price. From what I recall in my research(might have even been someone here) mentioned the manual was somehow a worse option than the auto.  I do think it would hold its value better—because rare—but if you're thinking SL, why not 500?

The manual is a dogleg and has more gears than the early auto, which is super useful considering this is a 3 liter in a fairly heavy car. It's a decent auto for the time but it will suck the life out a 6cyl r129 imo.  The fact that the 6cyl makes peak power at 6300 rpm makes the manual all the more enticing. Something with a manual that likes to rev is a basic recipe for fun.

500 has way more power but way less manual (100% less) and also takes up the whole engine bay so working on it will be different. Weight goes up on an already heavy car, and mostly in the front. If you don't care how fast it is I couldn't tell you it was better. If you do care then try to get a 5spd auto version over the 4spd auto. I got a v8 4spd auto because it was what came up on CL for $900. If I saw a 6cyl/5spd i would have bought that and been pretty much just as happy if not more so because the resale would be more multiples of what i paid. 

I have a 90s Mercedes Benz for fun. Extremely problematic. In fact it sits most of the time because I am afraid to drive it. Always has some issue.  I would never want an older MB for a high mileage commute but that's just me.  Have you considered a Lexus? Probably wouldn't be a manual but.........Just saying.

I've got one too.  Very rare, less than 200 made.  They only eat head gaskets if you let them overheat.  Mercedes plastics fall apart, be prepared for anything plastic to fall off or crack.  The top can be used mechanically, latches all have fittings and car should have wrench to work.  No big deal.  

In my opinion great drivetrain.  The motor makes torque and revs, shifter is decent but dog leg pattern is challenging in traffic.  If you keep your foot out of it expect mid 20s mileage.  7K for this is a pretty decent number