I have read a ton of info on all years of the Boxster and it appears that the 06 model year may just be a smart choice possibly over some of the other years.
Reasons: Last revision of the IMS bearing (not seeing any issues)
Last year of the 3.2L engine which was in production for a long time and was well tuned and the highest HP and Torque for that motor.
No Bore scoring issues that I have read about.This seems to be a problem with the 3.4L that was launched in 2007 ( I read that Porsche in addition to bigger jugs made revisions to the cooling system
that created even more issues mostly on tracked cars but also some daily drivers.
2006 had a different (superior )coating and material of the pistons and different coating on the cylinders. 2007 changed to a cheaper coating material obviously to save on cost.Jake Raby mentioned this in a post I read.
Please feel free to correct me on any information mentioned. Yes your wondering what year I have and yes I purchased this year due to everything I have read.So far with almost 100k I have experience
no issues other than routine maintenance.I do drive it hard but no track time.
If I had the cash I think I would purchase a 987.2 as there looking pretty good long term with lots of miles on them.

After looking back over Jake Rabys comments it appears the main diff between the change over from 06 to 07 was that Porsche changed the pistons from cast to forged.
Forged are stronger but unfortunately something in the design created borescoring problems. There have been virtually no borescoring issues on 06 and older motors.
FYI. Anyone thinking along the same lines with the 06 model year standing out as a good buy.