e-man

I'm sure this question has been asked at least a dozen times, but, after much searching, I've found lots of questions and few answers. I have a 1998 GS 400 with the stock Lexus/Pioneer premium stereo system, and have terrible FM stereo reception. Sometimes it's okay, but most of the time it's weak, hissing and crackling. Does anyone know if there's a way to get better reception? Is there such a thing as a signal amplifier? How about a second antenna or a replacement antenna? What about coating the rear window with aluminum foil? I'll do anything!!!!!!!!! Thanks.

e-man