I don't have any experience with those Hertz speakers but they say they are rated at 100W RMS and 200W peak. If I understand correctly that you are running those speakers on just one channel (say front for example) then you are feeding them 140W already, which is about what most folks would want to do (somewhere between RMS and peak rating). If you bridge the amp you would be pushing well over the peak rating all the time, which at best would make your speakers sound too bright and would most likely damage them when you turned up the volume.

If you want to improve your setup there are two things you could try that I did with that amp. The first thing is send your stock head unit to Iron Cross Audio in Henderson to have low level outputs installed. This cleans up the signal to where you can pretty much go full volume without serious distortion from those outputs. The signal is so clean I use AVC all the time with no distortion (as was OK'd by Iron Cross themselves). The only downside I have seen to the low level outputs IC installed was a loud pop due to a DC pulse in the outputs when you turned the head unit on or off. I just put a PAC SNI-1 ground loop isolator on each set of low level outputs and it did away with the problem entirely. They are pretty cheap so I didn't mind.

Also as a lot of us have discussed on other treads adding lower fairing speakers is one of the easiest ways to greatly improve the sound of your system. It doubles the volume in front of your face and gives you the ability to run PA mid bass speakers in the lowers which that amp can push just fine on the rear channel. Also by having the lower speakers on the rear channel you could blend them at will with the fader control on the handlebar. I haven't tinkered with speakers a lot but in my case running the Mmats 601.4 mid bass speakers in my lowers allowed me to push them harder than the coaxials I was running for a little more low end in the sound.

If you were to go that route you could easily put a DSP in the mix to individually tune your fairing speakers and lowers to sound the way you want them to. I added an ARC PSM DSP to my setup and the low level RCA outputs Iron Cross installed made it drop dead simple. I was then able to tame the brightness of my fairing speakers and set up the band pass frequencies that Mmats recommended for the lowers and I was very pleased with the sound. If the fairing speakers you have now do not sound too bright to you then you could easily do without the DSP and just use some FMODs to cap the high frequencies to the PA speakers in the lowers and the high pass filter of the amp to block the frequencies below 100Hz which most 6.5s can't reproduce.

I know some folks do not like the look of lowers on a Street Glide but I have seen that style sort of pick up lately. It's always been around when guys put the removable tour pak kit on their Ultra Classics. The CVO street glides now come with lowers with speakers in them from the factory as well. If you wanted to keep the airflow to your legs many companies make lowers that just have the speaker pods and leave your legs in the wind.

 

Bumping an old thread. I also just installed this amp with Infinity Kappa 62.11I's in the lower fairings and J&M Rokkers (6.5) in the fairing. and a KMM-BT525HD Kenwood head unit.
Is there anything different I need to do other than what was stated about setting the amp since this is not the stock HD head unit? What about the Kappa crossovers? They have a button for setting something? I need to read up on those.

Thanks!