Doesnt look like a bad design

but, they are leaving out some vital info on their supplied dyno sheets imo.

1. All sheets provided were in STD. (I would want to see dyno sheets in SAE and not STD correction factors.)
2. also, no afr datalogs were included. (for example: They could have run one car lean and the other at an ideal afr.)

Either way it looks like a quality made peice. The amount of gains will vary on YOUR supporting engine mods and a retune after install.