I use an R170 as a daily driver, it is lots of fun as is. The engine only revs to 5500 but has a lot of mid range torque. I am running a Kleemann boost pulley kit so the supercharger whines a bit more than stock, but I recommend it or similar.
https://catalog.kleemann.dk/catalog/cat ... ine/boost/ The engines are very stout internally as they are designed for boost and I am very tempted to turbo mine, however my other project takes priority/all the cash.
The front suspension as stock is quite a flexible design, you can feel it moving around under heavy braking and cornering. Rear end is great (IRS) and always feels very planted.
The manual version is rare, only about 10% were optioned from factory with them and they are not as strong as the autobox, but in a much lighter vehicle would be perfect.
The diff is not limited slip, but the stability control computer will pump the brakes on the spinning rear wheel to limit the slip. Great fun to drive the car with the stability control off, my kids have learned to do donuts in the paddocks in it. Nothing makes me prouder than my 8 year old catching and holding a drift with great counter steering.
One word of warning though - Mercedes were not in a good place when they built these and some have been unreliable. I have a real love/hate relationship with mine - love it when its going but hate it when it breaks down. A big part of that is it is not easy to get the factory data from Merc for servicing etc. Not DIY friendly. I had a seal fail in the supercharger gearbox and the oil leaked (a very distinctive smell, like really old diff oil) into the inlet and coated the MAF sensor and threw the A/F ratio out enough that the catalytic converter burned up and plugged up. A secondhand supercharger and new MAF and it didn't miss a beat. After 167,000 miles the original engine was swapped for a low mile spare that unbeknownst to myself and the guy selling it had a boost pulley on it that was worth more than I paid for the engine and trans!
Also the Vario convertible roof can be unreliable, costs a fortune to get fixed properly, but I keep my one working by manually opening and closing the hood a few times and it clears the lines and works again for a while - cheap fix!
Had been running on new engine for 8000 miles when the K40 relay block died and killed my ABS. Took me a really long time to work that one out. So touch wood hopefully it keeps going for the summer.
Ideally find one with a dead roof, duff ABS and stinky inlet tract with blocked cats - the owner will throw the car at you. A few hundred bucks later you will have a great powerplant.
Cheers,
Marcus.