Good analysis markluta. Although for me I found the interior to be least expensive for a couple of reasons. One, instead of purchasing new seat springs, I used spongy green foam (the durable kind) in all my seats. That in combination with the existing springs makes a better seat than original and at literally 1/1000 of the cost! Yes wow! Secondly in the case of leather interior, if it was a rip, I simply purchased a used seat at pga (ask for Pat!)and resurected the faded leather back into a new and original by using spray (yes, spray cans) from world upholstry with factory match original color dye. It never wears off after applied and looks new and highly durable. Works great on window trim and plastics as well!! I hope this saves someone up to $8000+- like it did me!!