Subs for a 1998 Olds Cutl--head unit question...?

No, you don't have to buy the head unit right now. However, if you are planning on getting it installed at circuit city it will cost more to get it installed later then installed now. You can use the method that sparky mentioned and that would work, however circuit city will most likely charge extra for this install. Plus, when you do get a deck put int they might even charge you again to hook up the amp to the new deck. I recommend telling an installer at circuit city what you want to do and seeing what they recommend or if you can work something out. Good Luck!!!