If you love it, and can afford it, BUY IT. Don’t regret. We don’t live forever and don’t know how long we will live.

As long as you can afford it, be a responsible adult with your family obligations, BUY!!!

Edit: damn low mileage. Just check service history what is due — brake rotors gonna cost a bomb, brake pads and suspension parts too. 9 years old… engine mounting, arms etc… will wear due to age.

You better get someone which is pro in Merc to check it out truly, usually good condition car people wont sell out so low unless he need money in short time or the ride got some issue. Check from chassis ( any recent accident repair done), ECU mods, engine modification done and try to ask for test drive with your mechanic & owner it in if possible. (high speed, low speed different kind of driving style)

Recently one of my friend sold off his Golf GTI also in low price due to ECU problem, when driven low speed no issue, but when go highway drive 140~160km/h for long period engine will shut off suddenly, he sent in few time mechanic to fix, from smoke leak test, pressure test and even on-drive OBD data analysis, sent for ECU repair, exchange also cannot fix and sell off fast. The new owner only test drive nearby and bought cash with him and did not notice it, sadly for sure most seller wont tell of their car weakness or issue openly. FYI, no engine fault code found on his ride ya, even the new owner come with OBD reader also cannot detect any fault codes. 

+1 on this

Drove this car before once and it sounds good even in stock form
Which gen was your friend's Gold GTI?

If not mistaken is MK6 generation.

The moral of the story is to get a proper mechanic to go test drive with the car on different road/style to check if the ride got issue.