1988 bmw 325si manufacture radio is missing but wiring cluster is intact apparently. Do i have to have a stock radio replacement or can i install a cd player deck without causing problems???

Generally you any after market radio can be installed into any car. You might have to cut the original wiring connector but basically all you need to hook up a basic radio/cd player is a positive and a ground wire. That's what powers the radio/cd player. Next all you need to do is hook up the speaker wires the unit. One other option is to check out ebay for a used radio/cd player. You will do better getting a radio that does not have an anti-theft feature. If it has an anti-theft feature you will have to enter a code to make it work.