Hi Kevin,
I built my own stainless sidepipes with parts from Stainless Specialties, and Summit. At the time, the mufflers were cheaper ($100 each polished) going through Summit even though they were made by SS. The total cost was about $650 in parts plus $100 to have 3/8" flanges cut by water jet. I used a hole saw for the mild steel flanges on the headers which I also made, but that was not a very good option for the stainless! I went with mild steel for the headers due to ease of cutting, and cost when I messed up. The headers ran about $200 in parts and are equal length +/- 1". I welded everything with my MIG, and did much finish work with a flap wheel on my angle grinder. MIG plus Grinder equals TIG
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I have some pics in my gallery that may help.
Good Luck!
Jon