Any lawyers here that know what is allowable when determining cost basis for a used aircraft? Thinking of selling my 172 and it's worth nearly double what I paid for it. The upgrades will obviously figure into the cost basis, and I would think acquisition costs (like prebuy) also. Lots of things have been replaced, but with newer/better components, so thinking that might be allowable since it's something that is actually sold with the plane. Guessing maintenance to keep it flying wouldn't be since it's not a business asset with depreciation and deductible expenses. Anyone know for sure?