Been awhile since I played Sims 2..how exactly do you add cars to the big spinning display thing for show/sell?

Just found out my dl'd skin isn't waterproof.She (my sim) owns a business and has many friends.Is there a way to change skins without starting over?

Kinda Sherlock Holms-ish eh?  (the title)

ANYWAY....I have tons of hacks/mods in my dl folder from various sites (including this one) and I seem to have a conflict which I can't figure out.. Anytime I get in the shower or hottub,my Sims body seems to disappear.I really don't want to have to do the remove mod,start up,remove mod,startup again method,which,while through,takes forever.I tried the conflict detector and nothing came up any ideas? Maybe a skin conflict...