are you getting another Z (TT)? If so I would find a way to get it first then start swapping stuff over. You will never get your money back on mods/upgrades unless you sign your title over to Universal Studios, buy it back and say it was in 2F2F (damn that looks ghey) and put on ebay.
Part it out and sell it stock would be your best $ option, but will take much longer. Just my 2cents.