I found these old forum threads which were a great help in understanding the differences between the models:
Differences in roadster versions [Archive] - Tesla Motors Club - Enthusiasts & Owners Forum
Roadster History North America [Archive] - Tesla Motors Club - Enthusiasts & Owners Forum
It seems like right now low-mileage 2.5s will usually run closer to $80k and up regardless of options, while low-mileage 1.5s can be found for as little as $55k. Originally I was focusing on 2.5s, but the more I think about the huge difference in price, the more I start to wonder what it is about the 2.5s I actually want and what I could do with an extra $20k. Some are no brainers; I'm sure there is some adapter that would allow me to switch out the old radio for a double-DIN touch-screen GPS system in a 1.5. Other features I wonder about, such as whether a 2.5 front bumper could be purchased for a 1.5 and what it would cost. Some I have no clue about, such as how the extra age will really affect battery life or what "improve reliability" means in the second post above. And with the price of the 3.0 upgrade still unknown, it's hard to know if it would be worth counting on saving the money to do a 1.5 > 3.0 conversion a year down the road...
So I thought it might be helpful to hear the thoughts of owners who have lived with their cars for years. What makes you glad you bought the model you did? What makes you wish you had waited for the newer model year? In short, if you were in the market now and cost was a limiting factor, would you aim for a clean 2008 that you could use the extra money to update, or would you definitely shoot for a 2.5 sport to get all the factory goodies?
Differences in roadster versions [Archive] - Tesla Motors Club - Enthusiasts & Owners Forum
Roadster History North America [Archive] - Tesla Motors Club - Enthusiasts & Owners Forum
It seems like right now low-mileage 2.5s will usually run closer to $80k and up regardless of options, while low-mileage 1.5s can be found for as little as $55k. Originally I was focusing on 2.5s, but the more I think about the huge difference in price, the more I start to wonder what it is about the 2.5s I actually want and what I could do with an extra $20k. Some are no brainers; I'm sure there is some adapter that would allow me to switch out the old radio for a double-DIN touch-screen GPS system in a 1.5. Other features I wonder about, such as whether a 2.5 front bumper could be purchased for a 1.5 and what it would cost. Some I have no clue about, such as how the extra age will really affect battery life or what "improve reliability" means in the second post above. And with the price of the 3.0 upgrade still unknown, it's hard to know if it would be worth counting on saving the money to do a 1.5 > 3.0 conversion a year down the road...
So I thought it might be helpful to hear the thoughts of owners who have lived with their cars for years. What makes you glad you bought the model you did? What makes you wish you had waited for the newer model year? In short, if you were in the market now and cost was a limiting factor, would you aim for a clean 2008 that you could use the extra money to update, or would you definitely shoot for a 2.5 sport to get all the factory goodies?