rough cost to fab that up, not including labor, which is the killer...
IC pipe $100-$125
IC (body) $300-$800
Y-pipe $100-$500 (depends on use of V-bads, premade merge, flange, etc etc.
Muffler $200-$350 depends on tips, V-bands, etc etc.
this is just a raw good estimate for the "fab" part...using SS and Aluminum.
I had about $2000 in mine, just in raw pipe and the IC body....I spent about 40 hours of fab time on it, then had someone weld up over my tack-welds.
You would be really hard pressed to DIY one yourself, without using used parts or junk parts for less than $6000
1500 TURBO
350 IC (air to air)
500 WG/BO
600 INJ
220 FUEL PUMP
1500 PIPEING
1500 MANAGEMENT
6170 TOTAL
at this rate, Cody's kit seems like a deal, since the labor is all done (welding)