Re: 2006 Cayman S vs 2010 Boxster Base - Recommendations?
Agree with Schwerer that you need to figure out if you want a coupe or a convertible before you can even begin.
I own both (an '06 Cayman S and an '09 Boxster base) because they are very different cars and I want what each one provides.
Some days are coupe days, and some days are convertible days. It's hard to explain, but you know it when you experience it.
An '06 Cayman S has 295HP whereas a base '09-'10 Boxster has 255HP, so the difference is 40HP and it is a noticeable difference.
I detect the difference between the two mostly in the torque though, finding the S slightly easier to drive around town without winding up the engine.
Neither is really underpowered until you take it to a track. And raw horsepower is not what Porsches have ever been about anyway. It is all about how they drive, transition, make you feel, etc.
I would recommend a 987.2 (2009-2012) Boxster over a 987.1 ('05-08) due to several upgrades, mostly to the engine/trans., and usually a newer car needs less in the way of maintenance or repairs.
Boxster does have less interior space than the Cayman, and if that is your criteria take a look at the difference.
A final observation that I will share is that driving the Cayman is like "wearing" the car. It is quick, responsive, mechanically alive (including engine/trans noise), and very confidence inspiring.
Driving the Boxster is more like riding in a car that is quick, responsive, and where the exterior and interior boundaries of the car blur. There is less perceived mechanical noise, more ambient noise (wind, dogs barking, the next vehicle over, etc.). To me it is more peaceful and restful to drive, and the sense of control at moderate speeds is nearly the same as the coupe.
To me the Boxster would not be my choice for taking to the track although the performance numbers can be very close between the two given the same engines, tires, etc. It's just more the difference in how each car "feels" to me.
Suggest you test each and see how they feel to you.
'06 Cayman S - 6MT
'09 Boxster - PDK