Babw said:
Test drive a 987 S as well. Your M54 car is dynamically a little less than an Z4M but with a little investment it can be better than the Z4M. BMW is nowhere near Porsche in dynamic terms and steering is a whole new league on the Boxster. Brakes as standard are also much better in feel and consistency.
My ownership in the last few years went something like - 335i, M3, 130i, 550i, Z4 and then I realised I was only considering cars from the BMW range, I'd developed badge snobbery without even trying the competition. Test drove a 981 Boxster and couldn't believe how good it was. Traded the 550i for an RS6 and now selling to M3 for a GTR. The Z4 still does the job of being a great small/fun daily. BMW are good but there are other manufacturers that make great cars also.
I mainly agree with your points here , all except when you say a "little" investment into a standard z4 will make it better than a z4M. I don't think so! Where do you start to get it feeling close ... Engine, brakes, suspension, LSD, engine, exterior changes, interior touches, hydraulic steering, engine