We're not reinventing the wheel here.... BMW only gave a NON-Manual gearbox in the CSL in 2003. The 360hp CSL rang rings around the GT3 (at the time) on track with no issues apart from a minor software upgrade.

Ferrari only gave a NON-Manual  gearbox in the 425hp 360 CS and 510hp F430 Scuderia. Both of these cars have been raced heavily on track continuously over the years.

If these manufacturers can do it then so can Porsche. If PDK is too heavy then ditch it and create a gearbox that works! ;)