168 hp was chosen as a limit for the non-Unicorn accounts mainly because the maximum width at that time was 168 hp, as seen in the Doepfer "monster cases". Since then, there's been some firms that have gone larger, most notably ADDAC System and their 197 hp (1 meter) cabs. Most starter cabs are below this width, so the higher width is really more of an "experienced user" requirement...hence why the widths beyond 168 hp are for the Unicorn users. But the Unicorn account is useful ALSO because you can create up to 60 separate builds...with that, you can build up multiple systems and then compare/contrast them to sort out the best approaches to your final desired result.