1991 Camaro Z28 Custom Exhaust?

I was planning on putting an exhaust system on my 91 Z28. I heard an exhaust on a 98 Z28 that I was trying to match. The system I am trying to match is the Loudmouth II series from SLP. I noticed SLP doesnt do much if anything for 3rd gen F-bodies like mine. So my initial plan was to by the mufflers and have the pipes done custom at this place Red Run in Ephrata Pa (if your familiar with my area). What else would I have to worry about to match the sound?