Another dumb exhaust question: clearence and silencers

[TheTimanator]

I will be going with the N1 or N1 dual. I read the reviews and I searched the forum but there wasn't much about clearence issues and the use of silencers so my questions are:

Is the N1 dual quiet enough to be driving on the highway without the silnecers in? do they come with them? I damage my hearing a lot with my last car so...I'm going to be really careful this time when it comes to loudness. (at cruzing speed, inside the car with the windows rolled up, it was 112 dbs! )

I read in one of the reviews that the N1 dual had clearence issuses. Is this true of the N1 single as well?

I will be installing am SR in the near future, so that will be a factor. BTW in case you missed it, I searched the forum already. Thanks for your help!