FM Modulator w/ IPOD

I have a Clarion marine deck. I dont know which model but it was the one they used in the 99 Mastercraft XStar. Obviously no RCA imputs for a good connection to an IPOD. I don't want to use the FM Transmitter b/c I have a pretty nice sytem and dont want to lose the quality. So I am considering either buying a new deck with RCA imputs or just using a FM modulator to get the RCA through the radio ant. Is there much of quality loss with the FM MOD. I would rather use this b/c a new deck is expensive and dont want to do that right now. Plus I have a FM Mod alread just not installed