Welcome,
Always nice to have more SS owners on the board - there is a wealth of information here. Make good use of the search function
Ebay might be your friend for the end cans - I'm actually looking to go the other way on my carby SS - I have Hi-level, but wifey was to be able to come out for the 'odd' ride and does not want her knees on her chin - (LOL - NO comments pls).
Depends if you want to remain road legal or not - I guess one way to go would be to get another set of standard cans and have them 'cored' - eg - packing and internals removed.
I'm not sure if the '03 models are fuel inj or not but if so - you would need to be looking for either another ECU or a power commander I imagine.
Good luck - Frank