What percentage of your car's purchase price do you have in mods?

what about stuff you transfer from car to car?

i bought newmans S13 for $3800, have about $25,000 worth of parts on it, but some of these parts i have had for upwards of 6 years.

so do i depreciate the parts by a set factor by year?

i will have an additional $5-6k into the car post most recent purchase