I wouldn't rely on that $100. I am also making my own twin pipes and I look to be leading the forward pipe down and out and the aft turbo up, back and down. Both will be something like 30-40cm long as I think that given the restriction in turbo size, that extra gain going all th way to the cats will reap nothing. I think as long as that dang junction is pegged, you'll fix most of the restriction.
God I hate insurance companies, those turbos would be gone long ago otherwise.
The pipes pictured look very cheap and a whole lot easier to make than the longer ones.