Buying an SL or no?

Hello! I am generally a lurker here but my wife and I are thinking about making a bad decision and I figure we can get some proper encouragement!!

My wife has always loved SLs from the 80's. She also loves red. We have a neighbor who is the original owner of a 1985 380, I believe in Signal Red, and it only has 66K miles. Almost everything is original, though he replaced the radio with a modern unit and the wheels were replaced along with new tires about 1000 miles ago. The original wheels had loose spokes and some rust. The replacements look period-correct, but I don't know any more about them right now. The car appears perfect, and he's about to put it up for sale for around $15-20K, likely near the higher end of that.

Today we took it for a test drive, and my wife is very tempted. We can afford it, but it feels very ridiculous to do so, particularly because this is car number 4 and we only have a 3 car garage, so our 2015 Venza will need to stay outside. My wife is a stay-at-home mom, and I work remotely, and I don't think we put more than 10K miles combined on the cars we have. This will also be our second car that the kids can't ride in, as I have an Elise. We typically only use our minivan...so is it a completely crazy idea to buy another cool car that we don't need? On the plus side, it seems like as long as we're paying less than $20K, there's not a lot of monetary downside. If we buy it and don't drive it enough, we could probably get out what we put into it a few years from now.

What else should we be thinking about with buying a 37 year-old car? The bit of research we've done indicates they are extremely well-built. All the maintenence is up to date with records, and he's even used the same independent mechanic for 15+ years (who happens to be German!).

Thanks in advance, I've learned a lot just hanging out around here! 

In reply to jtplaysdrums :

Life is short and it sounds like you can afford it. I'm not an expert on the r107, but I think the 380 had issues with the timing chain. Having one original owner is really nice, but make sure to get a PPI at an independent shop that is familiar with these cars. As for the garage space, nobody is going to care if you leave a 2015 Venza outside =)

Overview of TC issues on the 380SL: https://www.benzworld.org/threads/380sl-double-row-timing-chain-conversion.1395279/

Good luck, and tell us what you decide!

In reply to jtplaysdrums :

Be aware that the flat rate manual does not apply to older cars.  Rusty bolts  become a wrestling match and can add many hours to a job.   
  Wiring is age limited.  The plastic insulation cracks and causes weird effects. Some things will be replaced that are still in good shape but that's the standard trouble shooting method used. So items costing  hundreds maybe even thousands will be replaced  and when it fails and you bring it back don't expect a refund.  Replacing the wiring loam  is a horribly expensive prospect.    
    Then there is rubber.  Doesn't matter if it's controlling the engine,( vacuum) the coolant, ( engine, HVAC) brakes  or what.    They all age out.  

Those are great little cars.  They don't make great cars like that any more.  Does it have the hard top?

Also, NB : Happy wife, happy life

Thank you for all the thoughtful responses! She decided yes, and bought it today!

In reply to jtplaysdrums :

they look nice together!

I was going to say heavy and slow, until I saw the garage mate. Think you have it all covered!

A friend owns a 450 SL - looks nice, isn't fast and uses a fair bit of gas but no problems with it otherwise.

Nicely done.  

Those things are built like a bank vault.  Lenny Dykstra failed to kill himself drunkenly driving his into a tree at a high rate of speed.  

Your wife certainly has grown up judgement, rather than drunken hillbilly judgement, so it will probably not come up, but nice to know the wife is rolling in a vault from Stuttgart.

Very nice and congratulations.