Most 2-1 exhaust systems won't do a thing. The Cobra Power Pro will....

Vadose, can you add a pix? I'd like to see them! Thx. 

I have not purchased them yet. Just wanting to get some opinions  if  the 2-1 pipes  will increase HP.

I much prefer the sound out of the HK 2.75 big straights and the look. They were my first after market exhaust. I replaced them with a 2 into 1 for more HP and have regretted it ever since. Only recently was I once again able to replace them with the HK 2.75 big straights and I am very happy. 

Did you notice a significant power increase with the 2-1s? Did you put the Cobra 2-1's on?.

I did notice a slight increase in HP (seat of the pants dyno), but it sounded more like a hemi with the 2 into one pipes than the individual potato potato sound coming out of 2 separate pipes that I personally prefer along with the look.

Thanks evwy8ne for the responses! I am going to keep  my existing  exhaust. I can't justify the cost of new pipes yielding a minor HP gain. I also love the look of my Big Straights over a 2-1 system. I am going to change out the baffles to quite them down a bit thuogh. Anyone here using the Big City Thunder Quiet Baffles? I have their lollipop installed now  and they  sound good but a pretty loud.

To answer your question. About 5hp with the Cobra 2:1, it's the only 2:1 performance made for the 1100.

You can also try torque cones....pretty easy install that will quiet them a little....plus add a little low end. Just look for them sized for a Shovelhead.