They are out of business. I was looking for part for my 4:2:1:2 pipe and ended up having to build them.
Check around from some of their old distributors and see if they have anything laying around.
You may have to get silencers from someone else and make them fit.
Too bad they are gone, their pipes were reasonably priced, beautifully welded, fit great and in my case worth about 14hp over stock.