The PC is a more popular choice as compared to the Yoshimura EMS cube... but the EMS cube has features in it that really look tempting... for example, You can load three different maps into it, and switch between them for your specific purpose!! If im not wrong...it also has support for a air-shifter!! I dont know in what way its infirior to the PC though... you might want to talk to a tuner about it!
...As far as the the performance is considered with respect to mountings... well there is no difference!! Hi mount, low mount... stock mount, how ever you mount makes absolutely no difference to the Performance!!