Which Boxster S would be a better purchase in the long run?

[tomonomics]

You could also add an extra 8 horses to the 2003S. And remove the roof, radio, and A/C like they did with the Spyder, but you would end up with a car that I would not want to drive very often.

Unless you're building a spec boxster for the track (which I did not think the OP was intending to do), the stock weight/HP numbers are very similar and would not persuade me to buy an older model with more mileage. I guess we'll just agree to disagree.

[The French Dude]

FYI my 2003 Box S has dual row IMSB
Don't ask me why...

[Perfectlap]

Originally Posted by tomonomics

Unless you're building a spec boxster for the track (which I did not think the OP was intending to do), the stock weight/HP numbers are very similar and would not persuade me to buy an older model with more mileage. I guess we'll just agree to disagree.

If mileage is similar, the market will give you a much better discount on purchase price for an older car for pretty much the same power/weight proposition.
Hence (imho) 1997-1999 is essentially the same car, 2000-2004, 2005-2008, 2009-2011. I would be steering towards lower miles in each year range, with an emphasis on cars that lived in mild climates that do not see extreme hot or cold. This makes it more likely that the car was driven year round and in less punishing weather.