Car - Tax versus Shipping Costs

[Speedster]

For all of you PT car wheeler-dealers, especially in California - do you know if it is cheaper to buy a new car in Florida and ship it to California for major work or better to buy it in California, have it worked on there and save the shipping. In other words, does California have a deal with other states so you don't have to pay extra sales tax ? Is there a time limit ? Basically, if the tax is the same, then it could save a cross country shipping fee. Thanks.