Are there major differences between.......
 

the 2005, 2006, and 2007 Boxster S?

I know that the engine has changed from 2.7 to 3.2 to 3.4 (is this just bored differently, or different engines?) How about wiring and general mechanical things, i.e., switches, layout of the cabin, gauges, etc. Or is everything basically the same with only a few minor cosmetic changes?

Thanks.

Actually, in the model years you mention, the Boxster S went from 3.2 to 3.4. The 2.7 was and still is, offered in the base Boxster version. In 05 and 06, the Boxster S had 3.2L engine with 280hp. The 3.4L S for 07 has 295hp. The differences inside the car are pretty much the same, with no major changes between the model years. Not much in terms of exterior changes either.

I also think the 07 now has the same version of Variocam as the 911. Flatter torque curve and better fuel economy then the 06.

One big difference with the 2005 and 2006 Boxster was the use of different airbag technology. In my 2006 the passanger airbag will automatically turn off if the person sitting there is is less than a certain weight (I think < 100 pounds). This is great if you have young children. You should still use the proper child seat or booster seat, but you don't need Porsche's super expensive airbag deactivation kit. I think this saved me about $1,000 in labor & parts.