[drburton]

I have an 05 Boxster S and I feel the car is well balanced, but everyone can always use more power - right. I have never driven the ZM4, but here are some things to think about:

Appearance:
This is subjective, but I think the Boxster is a much better looking car, the Z4's long hood short backend just doesn't work for me.

Handling:
With the Boxster you can be a novice driver and still have a blast through some twisties with little concern about losing control of the car. The Z4 takes more talent to master, backend will get out on you. But, once mastered, the Z4 could be more fun, dependent you your driving style.

Acceleration (ie Power)
This obviously favors the BMW, but the Boxster S can hit 60 in 5.1 seconds, which is still pretty damn fast.

Community
I will say owning a Porsche is something special b/c of the 'community' and shared enthusiasm about the car. The PCA is a wonderful organization.

Ultimately, depends on your driving style and what you expect out of the car, but I am one very happy Boxster owner. Good Luck.