I think all this "write-off" talk is somewhat confusing to many people. If somehow you are able to "write-off" something, legally or illegally, it still is not free and Uncle Sam is not paying for it.
You pay real 100% dollars to purchase it and to use it. That expense when "written-off" becomes a reduction in income that ultimately results in about a 40% savings on that income if you are in the highest marginal tax bracket.
That $300,000 Ferrari, if somehow qualified as tax deductible, would produce $11,260 in depreciation the first year plus the operating costs based on the percentage of qualified business use and commuting does not count. Hardly a "free" car after a $300,000 outlay.