I have been thinking about purchasing a Prius. but I live in CA, where there's no state tax incentives. but I have a relative in Colorado. is it best to get it there? what are the most incentives? and how?

I have some starting points:

1. co-own it with the relative, or,
2. he buys it for me.

is the tax credit transferable especially for #2 above?

I figure that either way it will have to be registered and used in CO for some time before I can have it. registration there is required to claim the credit. and if I bring the car into CA too soon, there's also a hefty excise tax. or is that abolished? what's the registration fee in CO?

if the friend also proves he sold a much older car that the Prius "displaces", the credit is more (100% instead of 75% earlier). is that before or after the prius purchase? does it matter if both transactions are done in the same year?

lastly, what's the sales tax for hybrid cars in say, Denver?