Need your opinion on Catalytic and Muffler

I have to buy in few months an new Catalytic and muffler for my 1984 633csi, Wow $$$$. The car is store during all winter in a heated garage and has an oil treatment every year. Part dealers have on hands Bosal, Ansa, Eatem, Miller, Germany OEM, Bavarian has his own product, etc. My questions are:
-Which brand would you choose as catalytic, as muffler?
-Should I buy steel or stainless steel?
-Which one has a better 'sport sound'?

Thanks