Interesting thread. I had a 135i and my wife had a 125i for about 2 years. We bought both cars at the same time. I love the 125i every time I jumped in - the balance and that engine was just beautiful. It is what BMW was all about. I still think the 125i is a much more balanced and better handled package than the 135i.
However, whenever I jumped back in the 135i, I realised that torque is so addictive.