carpy says that Pops from the original Yoshimura is building these for him as he lives in CA now.
he gets them made in batches of like 15-20 at a time, although i don't know that at all, i'm just making assumptions from his websites pictures.
he says you don't need a rear bracket, but i'd rather not have my cylinder head supporting the weight. the whole pipe starts to act as a long moment arm, and bumps and vibrations from the road will amplify themselves a LOT on the mounting bolts and flanges, and i wouldn't want to do anything like that... i don't like this at all, but being an engineer doesn't help any ignorance in this matter at all. i will probably either weld a bracket (not the cleanest) or get some psuedo-schnazzy bracket that wraps around it.
and bending a pipe like that, NOT easy, otherwise the market would be flooded by them. especially with the tight radius curves under the engine and the constant diameter increase of the end. they are fully mandrel bent from what i can see, with no kinking, which is hard to do with anything but the best mandrel benders. $400 is a damn good deal for a 4-1 period. i'd suggest anyone wanting one should support carpy and these great pipes.