[crayzayjay]

One thing to consider is that the Boxster is being replaced soon, the M3 is also in the later stages of its life with the new 3-series coming in next year. The S4 is the most recently introduced of the 3 cars you mention, but is the least sporty in terms of driving experience. It's very fast but feels a bit 'cold' and isnt as involving as an M3 or Boxster. The Boxster S isnt as quick (straight line) as an M3), but handles better; both are easy to live with though brakes can sometimes be troublesome on the Boxster. Personally, i'd wait until the new model comes out. The interior will have been smartened up and you'll be buying a new model.