Tiger's number at A1 is 714-836-7201. A 1-3/4" primary tube header (no muffler) in raw finish is less than $300. It's a screamin' deal.
I think you may have misunderstood the nature of Serrano's- they were a bottom-feeding engine shop that branched out into parts resale a few years ago. They didn't make anything. As far as I can tell, with custom exhausts, and DTMs, and all other specialized part from other sources-- he'd buy big batches, and then resell them cheap. The prices really were intoxicating, and unrealistic. I got everything I ever ordered, but I should have known better than to play with fire.
As far as the lost money-- if you go over on the Samba, you'll come away with a bad feeling in the pit of your stomach. I really doubt you'll ever see your money, or exhaust again. Steve took people for thousands of dollars, and took money right up to the day he shut the doors.
Within a year, I hope to have my 1-5/8" A1 Sidewinder header with about 3000 mi on it for sale. I'll shoot you an email when I'm ready to sell.
My advice for now? Contest the charges on your card right now-- let the credit card company duke it out.
Good luck.