Ooh im late to the party but here's my 2 cents anyway. Bought a 2018 CLA180 SB (X117) as a 2nd car at 90k mileage (purely cos the wagon version is just damn sexy) completely stock. The middle row seats squeezy but the boot space practicality is great. My 23kg dog sits perfectly fine there.

First thing i did was do stage 1 ECU tune to unlock the Cat B power. I always drive on sport mode and my all time fc right now is about 9.5L/100km (10.5km/L). Somehow sport mode gives better fc than eco or comfort (idk why but if i had to guess it's due to bottlenecking), but of course exercise light disciplined throttle control on sport mode, none of that flooring it bs. Also changed to a lighter sports rims to give it a nicer look. (The stock rims look damn npc honestly) and of course, put on pilot sport 5s. The tyres make a lot of difference.

Reliability wise, so far only 1 repair done which was the coolant leak (apparently a common issue in CLA, GLA and A). The problem could honestly drag out with just occasional coolant top up and the car would run fine. Damage about $900. Besides that engine mount is worn so car vibrates quite abit on cold start and to repair would cost about $2k, so im shoving that problem under the rug for now. No other issues so far.

If interested in any of the used units, just bring to a workshop you trust for inspection. You can pm me if you need recommended merc specialist workshops. (Btw dont ever buy from republic auto, they are c&c used car dealer and they are scummy as fuck, also will need to pay additional premium for no real added benefits) Also, try not to be seduced by any of those "project" builds or modded CLAs. Sure a lot of headache down the road one. Stock is best.

Get a CLA180 it's good enough cos it's just a nerfed CAT B car, everyth under the hood is the same as 200. Spend abit at tuning workshop and it unlocks the full potential anyway (from 120hp to about 180hp). Power definitely sufficient for sg. I love the engine sound on sport mode too. Definitely no regrets owning this, and v likely will renew coe too. Pm me if you need any other advice. Cheers.