Differences b/w stock 17's & 19's?
 

I am looking to change wheels in the near future.

Does anyone know the weights of the stock 17 inchers? Search function isn't working.

I am looking at changing to something like the Axis Hiro. What are my tradeoffs going to be? This is my primary car. Will the ride be too harsh for day to day with the bigger rims? I have to assume that changing tires and bigger rims should help my handling. Will they be slowing me down (performance wise) at all? Will they have any effect on my speedo accuracy?

Should I really be looking into 18's for daily driveability? If so.. any suggestions?

Well your car is going to be a little slower because those Axis rims weigh quite a lot compared to the stock 17's. I would just get some lightweight 18's if you want performance and style from rims.