if all ur install is done properly, i believe ur bottleneck is on the hu itself..u may wan to get that done

Coz the hu lack of some eq band and tuning function.

bottle neck is not restricted to traffic jams if you're familiar with IT terms, bottle neck is simply having the weakest link in the system:

eg: your graphic card is a geforce titan, ram 32GB DDR3 triple channeled, HDD ssd RAID 0'd, however you're on a core 2 duo 1.6ghz.
the processor is easily the bottleneck where by all the other components have to wait for the processor's pending processing before they can proceed to process their operation (eg: graphic to generate frames, RAMs to store volatile data to reduce HDD swap, however processor haven't done processing the data graphic/RAMs required)

thus, bottleneck